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  • JQuery not removeing added element

    - by Scott
    What I want to do is add and remove list items. I have got it to add new items to the list and I can remove existing ones but not the ones that have been added. It seem like it would work but it doesn't. Any help would be appreciated! Here the code: JQuery: <script type="text/javascript"> $(function(){ $('a#add').click(function(){ $('<li><a href="#" id="remove">--</a>List item</li>').appendTo('ul#list'); }); $('a#remove').click(function(){ $(this).parent().remove(); }); }); </script> HTML: <a href="#" id="add">Add List Item</a> <ul id="list"> <li><a href="#" id="remove">--</a> List item</li> <li><a href="#" id="remove">--</a> List item</li> <li><a href="#" id="remove">--</a> List item</li> <li><a href="#" id="remove">--</a> List item</li> </ul>

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  • Where is a small, simple CMS that has no Front End done in PHP?

    - by user559469
    The keys are: small and simple PHP MySql no Front End By "no front end" I mean literally, I can control the look 100%. I just want a CMS on the "backend" to manage content (user login/security, upload images, udate articles, etc.) that will not dictate in anyway how the managed data is presented. Maybe it just keeps the info in a (MySql) database (which I can query and extract myself) or if it writes content, it is in super-clean xhtml fragments or even just xml I will parse myself? I have looked at Wordpress -- and don't like the code it generates, not to mention the sites look too "canned" (you can usually spot a WP site a mile a way.) Joomla and Drupal look more customizable, but they are bloated now in my opinion, and really I just want something lightweight and simple. For one-user mom-and-pop sites. (No tiered publishing/approval systems, and all that.) I envision plugging this CMS into existing websites/web apps where most of the site is made and managed by me, but a few choice areas are managed by the site owner.

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  • Optimal (Time paradigm) solution to check variable within boundary

    - by kumar_m_kiran
    Hi All, Sorry if the question is very naive. I will have to check the below condition in my code 0 < x < y i.e code similar to if(x > 0 && x < y) The basic problem at system level is - currently, for every call (Telecom domain terminology), my existing code is hit (many times). So performance is very very critical, Now, I need to add a check for boundary checking (at many location - but different boundary comparison at each location). At very normal level of coding, the above comparison would look very naive without any issue. However, when added over my statistics module (which is dipped many times), performance will go down. So I would like to know the best possible way to handle the above scenario (kind of optimal way for limits checking technique). Like for example, if bit comparison works better than normal comparison or can both the comparison be evaluation in shorter time span? Other Info x is unsigned integer (which must be checked to be greater than 0 and less than y). y is unsigned integer. y is a non-const and varies for every comparison. Here time is the constraint compared to space. Language - C++. Now, later if I need to change the attribute of y to a float/double, would there be another way to optimize the check (i.e will the suggested optimal technique for integer become non-optimal solution when y is changed to float/double). Thanks in advance for any input. PS : OS used is SUSE 10 64 bit x64_64, AIX 5.3 64 bit, HP UX 11.1 A 64.

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  • Suggestions on Working with this Inherited Generic Method

    - by blu
    We have inherited a project that is a wrapper around a section of the core business model. There is one method that takes a generic, finds items matching that type from a member and then returns a list of that type. public List<T> GetFoos<T>() { List<IFoo> matches = Foos.FindAll( f => f.GetType() == typeof(T) ); List<T> resultList = new List<T>(); foreach (var match in matches) { resultList.Add((T)obj); } } Foos can hold the same object cast into various classes in inheritance hierarchy to aggregate totals differently for different UI presentations. There are 20+ different types of descendants that can be returned by GetFoos. The existing code basically has a big switch statement copied and pasted throughout the code. The code in each section calls GetFoos with its corresponding type. We are currently refactoring that into one consolidated area, but as we are doing that we are looking at other ways to work with this method. One thought was to use reflection to pass in the type, and that worked great until we realized the Invoke returned an object, and that it needed to be cast somehow to the List <T>. Another was to just use the switch statement until 4.0 and then use the dynamic language options. We welcome any alternate thoughts on how we can work with this method. I have left the code pretty brief, but if you'd like to know any additional details please just ask.

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  • Use jQuery.post() result in javascript function

    - by Juvlius
    I've got no clue how to do the following, so I wasn't sure what to search for either. For validating my registration form I've a javascript function that checkes the existence of the inserted username in the database onblur of the username textfield. function checkUsername(username){ $.post("checkmail.php", {mail: mailcheck} , function(data){ var $response=$(data); var response = $response.filter('#mail-response').text(); if(response == "taken") { document.getElementById('username').style.borderColor = rood; valid = false; } }); } This works fine, but now I want to validate it again onsubmit of the form in case users decide to submit an existing username. function validateForm() { var valid = true; //checks different fields //now check voor username existence var username = document.getElementById('username').value; checkUsername.call(username); if (!valid) { return false; } else { return true; } } I'm not familiar enough with Javascript to get this working. Probably thinking in the wrong direction...

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  • Remove a ReactiveCocoa signal from a control

    - by dbarros
    If I assign a signal to a property of a control: RAC(self.loginButton.enabled) = [RACSignal combineLatest:@[ self.usernameTextField.rac_textSignal, self.passwordTextField.rac_textSignal ] reduce:^(NSString* username, NSString* password) { return @(username.length > 0 && password.length > 0); }]; But then wanted to assign a different RACSignal to enabled, how can I clear any existing one before doing so? If I try and set it a second time, I get an exception like the following: 2013-10-29 16:54:50.623 myApp[3688:c07] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Signal <RACSignal: 0x975e9e0> name: +combineLatest: ( "<RACSignal: 0x975d600> name: <UITextField: 0x10f2c420> -rac_textSignal", "<RACSignal: 0x975de30> name: <UITextField: 0x10f306e0> -rac_textSignal" ) reduce: is already bound to key path "self.loginButton.enabled" on object <LoginViewController: 0x10f264e0>, adding signal <RACSignal: 0x9763500> name: +combineLatest: ( "<RACSignal: 0x97624f0> name: <UITextField: 0x10f2c420> -rac_textSignal", "<RACSignal: 0x97629e0> name: <UITextField: 0x10f306e0> -rac_textSignal" ) reduce: is undefined behavior'

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  • Calling child constructor by casting (ChildClass)parentObject; to track revisions

    - by FreshCode
    To track revisions of a Page class, I have a PageRevision class which inherits from Page and adds a revision ID (Guid RevisionID;). If possible, how should I cast an existing Page object to a PageRevision and ensure that the PageRevision constructor is called to create a new revision ID? I could could have a PageRevision(Page page) constructor which generates the Guid and copies all the Page attributes, but I want to automate it, especially if a Page class has many attributes (and I later add one, and forget to modify the copy constructor). Desired use Page page = new Page(123, "Page Title", "Page Body"); // where 123 is page ID PageRevision revision = (PageRevision)page; // now revision.RevisionID should be a new Guid. Page, PageRevision classes: public class Page { public int ID { get; set; } public string Title { get; set; } public string Body { get; set; } } public class PageRevision : Page { public Guid RevisionID { get; set; } public PageRevision() { this.RevisionID = Guid.NewGuid(); } }

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  • Ruby on Rails: temporarily update an attribute into cache without saving it?

    - by randombits
    I have a bit of code that depicts this hypothetical setup below. A class Foo which contains many Bars. Bar belongs to one and only one Foo. At some point, Foo can do a finite loop that lapses 2+ iterations. In that loop, something like the following happens: bar = Bar.find_where_in_use_is_zero bar.in_use = 1 Basically what find_where_in_use_is_zero does something like this in as far as SQL goes: SELECT * from bars WHERE in_use = 0 Now the problem I'm facing is that I cannot run the following line of code after bar.in_use =1 is invoked: bar.save The reason is clear, I'm still looping and the new Foo hasn't been created, so we don't have a foo_id to put into bars.foo_id. Even if I set to allow foo_id to be NULL, we have a problem where one of the bars can fail validation and the existing one was saved to the database. In my application, that doesn't work. The entire request is atomic, either all succeeds or fails together. What happens next, is that in my loop, I have the potential to select the same exact bar that I did on a previous iteration of the loop since the in_use flag will not be set to 1 until @foo.save is called. Is there anyway to work around this condition and temporarily set the in_use attribute to 1 for subsequent iterations of the loop so that I retrieve an available bar instance?

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  • JPA entity relations are not populated after .persist()

    - by Tomik
    Hello, this is a sample of my two entities: @Entity public class Post implements Serializable { @OneToMany(mappedBy = "post", fetch = javax.persistence.FetchType.EAGER) @OrderBy("revision DESC") public List<PostRevision> revisions; @Entity(name="post_revision") public class PostRevision implements Serializable { @ManyToOne public Post post; private Integer revision; @PrePersist private void prePersist() { List<PostRevision> list = post.revisions; if(list.size() >= 1) revision = list.get(list.size() - 1).revision + 1; else revision = 1; } So, there's a "post" and it can have several revisions. During persisting of the revision, entity takes a look at the list of the existing revisions and finds the next revision number. Problem is that Post.revisions is NULL but I think it should be automatically populated. I guess there's some kind of problem in my source code but I don't know where. Here's my "persistence" code: Post post = new Post(); PostRevision revision = new PostRevision(); revision.post = post; em.persist(post); em.persist(revision); em.flush(); I think that after persisting "post", it becomes "managed" and all the relations should be populated from now on. Thanks for help! (Note: public attributes are just for demonstration)

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  • No route matches [PUT] error in active_admin

    - by Alex
    in active_admin partials created a form input: <%= semantic_nested_form_for @item, :url => admin_items_path(@item) do |f| %> <fieldset class="inputs"> <ol> <%= f.input :category %></br> <%= f.input :title %> <%= f.input :photo1 %> <%= f.input :photo2 %> </ol> </fieldset> <%= f.fields_for :ItemColors do |i| %> <fieldset class="inputs"> <ol> <%= i.input :DetailColor %> <%= i.input :size, :input_html => { :size => "10" } %> <%= i.link_to_remove "remove" %> </ol> </fieldset> <% end %> <%= f.link_to_add "add", :ItemColors %> <%= f.actions %> <% end %> to create a new Item okay creates and throws On the New Item, but if I do update an existing item is routed to an error occurs while such a path exists: No route matches [PUT] "/admin/items.150" #150 is item_id rake routes: batch_action_admin_items POST /admin/items/batch_action(.:format) admin/items#batch_action admin_items GET /admin/items(.:format) admin/items#index POST /admin/items(.:format) admin/items#create new_admin_item GET /admin/items/new(.:format) admin/items#new edit_admin_item GET /admin/items/:id/edit(.:format) admin/items#edit admin_item GET /admin/items/:id(.:format) admin/items#show PUT /admin/items/:id(.:format) admin/items#update DELETE /admin/items/:id(.:format) admin/items#destroy help to solve this problem UPD I found the error, but not yet understood how to fix it the upgrade is a request: PUT "/admin/items" but should: PUT "/admin/items/some_id" any ideas?

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  • Is it wrong for a context (right click) menu be the only way a user can perform a certain task?

    - by Eric
    I'd like to know if it ever makes sense to provide some functionality in a piece of software that is only available to the user through a context (right click) menu. It seems that in most software I've worked with the right click menu is always used as a quick way to get to features that are otherwise available from other buttons or menus. Below is a screen shot of the UI I'm developing. The tree view on the right shows the user's library of catalogs. Users can create new catalogs, or add and remove existing catalogs to and from their library. Catalogs in their library can then be opened or closed, or set to read-only. The screen shot shows the context menu I've created for the browser. Some commands can be executed independently from any specific catalog (New, Add). Yet the other commands must be applied to a specifically selected catalog (Close, Open, Remove, ReadOnly, Refresh, Clean UP, Rename). Currently the "Catalog" menu at the top of the window looks identical to this context menu. Yet I think this may be confusing to the users as the tree view which shows the currently selected catalog may not always be visible. The user may have switched to the Search or Filters tab, or the left pane may be hidden entirely. However, I'm hesitant to change the UI so that the commands that depends on a specifically selected catalog are only available through the context menu.

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  • NuGet package manager in Visual Studio 2012

    - by sreejukg
    NuGet is a package manager that helps developers to automate the process of installing and upgrading packages in Visual Studio projects. It is free and open source. You can see the project in codeplex from the below link. http://nuget.codeplex.com/ Now days developers needed to work with several packages or libraries from various sources, a typical e.g. is jQuery. You will hardly find a website that not uses jQuery. When you include these packages as manually copying the files, it is difficult to task to update these files as new versions get released. NuGet is a Visual studio add on, that comes by default with Visual Studio 2012 that manages such packages. So by using NuGet, you can include new packages to you project as well as update existing ones with the latest versions. NuGet is a Visual Studio extension, and happy news for developers, it is shipped with Visual Studio 2012 by default. In this article, I am going to demonstrate how you can include jQuery (or anything similar) to a .Net project using the NuGet package manager. I have Visual Studio 2012, and I created an empty ASP.Net web application. In the solution explorer, the project looks like following. Now I need to add jQuery for this project, for this I am going to use NuGet. From solution explorer, right click the project, you will see “Manage NuGet Packages” Click on the Manage NuGet Packages options so that you will get the NuGet Package manager dialog. Since there is no package installed in my project, you will see “no packages installed” message. From the left menu, select the online option, and in the Search box (that is available in the top right corner) enter the name of the package you are looking for. In my case I just entered jQuery. Now NuGet package manager will search online and bring all the available packages that match my search criteria. You can select the right package and use the Install button just next to the package details. Also in the right pane, it will show the link to project information and license terms, you can see more details of the project you are looking for from the provided links. Now I have selected to install jQuery. Once installed successfully, you can find the green icon next to it that tells you the package has been installed successfully to your project. Now if you go to the Installed packages link from the left menu of package manager, you can see jQuery is installed and you can uninstall it by just clicking on the Uninstall button. Now close the package manager dialog and let us examine the project in solution explorer. You can see some new entries in your project. One is Scripts folder where the jQuery got installed, and a packages.config file. The packages.config is xml file that tells the NuGet package manager, the id and the version of the package you install. Based on this file NuGet package manager will identify the installed packages and the corresponding versions. Installing packages using NuGet package manager will save lot of time for developers and developers can get upgrades for the installed packages very easily.

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  • Creating a Build Definition using the TFS 2010 API

    - by Jakob Ehn
    In this post I will show how to create a new build definition in TFS 2010 using the TFS API. When creating a build definition manually, using Team Explorer, the necessary steps are lined out in the New Build Definition Wizard:     So, lets see how the code looks like, using the same order. To start off, we need to connect to TFS and get a reference to the IBuildServer object: TfsTeamProjectCollection server = newTfsTeamProjectCollection(newUri("http://<tfs>:<port>/tfs")); server.EnsureAuthenticated(); IBuildServer buildServer = (IBuildServer) server.GetService(typeof (IBuildServer)); General First we create a IBuildDefinition object for the team project and set a name and description for it: var buildDefinition = buildServer.CreateBuildDefinition(teamProject); buildDefinition.Name = "TestBuild"; buildDefinition.Description = "description here..."; Trigger Next up, we set the trigger type. For this one, we set it to individual which corresponds to the Continuous Integration - Build each check-in trigger option buildDefinition.ContinuousIntegrationType = ContinuousIntegrationType.Individual; Workspace For the workspace mappings, we create two mappings here, where one is a cloak. Note the user of $(SourceDir) variable, which is expanded by Team Build into the sources directory when running the build. buildDefinition.Workspace.AddMapping("$/Path/project.sln", "$(SourceDir)", WorkspaceMappingType.Map); buildDefinition.Workspace.AddMapping("$/OtherPath/", "", WorkspaceMappingType.Cloak); Build Defaults In the build defaults, we set the build controller and the drop location. To get a build controller, we can (for example) use the GetBuildController method to get an existing build controller by name: buildDefinition.BuildController = buildServer.GetBuildController(buildController); buildDefinition.DefaultDropLocation = @\\SERVER\Drop\TestBuild; Process So far, this wasy easy. Now we get to the tricky part. TFS 2010 Build is based on Windows Workflow 4.0. The build process is defined in a separate .XAML file called a Build Process Template. By default, every new team team project containtwo build process templates called DefaultTemplate and UpgradeTemplate. In this sample, we want to create a build definition using the default template. We use te QueryProcessTemplates method to get a reference to the default for the current team project   //Get default template var defaultTemplate = buildServer.QueryProcessTemplates(teamProject).Where(p => p.TemplateType == ProcessTemplateType.Default).First(); buildDefinition.Process = defaultTemplate;   There are several build process templates that can be set for the default build process template. Only one of these are required, the ProjectsToBuild parameters which contains the solution(s) and configuration(s) that should be built. To set this info, we use the ProcessParameters property of thhe IBuildDefinition interface. The format of this property is actually just a serialized dictionary (IDictionary<string, object>) that maps a key (parameter name) to a value which can be any kind of object. This is rather messy, but fortunately, there is a helper class called WorkflowHelpers inthe Microsoft.TeamFoundation.Build.Workflow namespace, that simplifies working with this persistence format a bit. The following code shows how to set the BuildSettings information for a build definition: //Set process parameters varprocess = WorkflowHelpers.DeserializeProcessParameters(buildDefinition.ProcessParameters); //Set BuildSettings properties BuildSettings settings = newBuildSettings(); settings.ProjectsToBuild = newStringList("$/pathToProject/project.sln"); settings.PlatformConfigurations = newPlatformConfigurationList(); settings.PlatformConfigurations.Add(newPlatformConfiguration("Any CPU", "Debug")); process.Add("BuildSettings", settings); buildDefinition.ProcessParameters = WorkflowHelpers.SerializeProcessParameters(process); The other build process parameters of a build definition can be set using the same approach   Retention  Policy This one is easy, we just clear the default settings and set our own: buildDefinition.RetentionPolicyList.Clear(); buildDefinition.AddRetentionPolicy(BuildReason.Triggered, BuildStatus.Succeeded, 10, DeleteOptions.All); buildDefinition.AddRetentionPolicy(BuildReason.Triggered, BuildStatus.Failed, 10, DeleteOptions.All); buildDefinition.AddRetentionPolicy(BuildReason.Triggered, BuildStatus.Stopped, 1, DeleteOptions.All); buildDefinition.AddRetentionPolicy(BuildReason.Triggered, BuildStatus.PartiallySucceeded, 10, DeleteOptions.All); Save It! And we’re done, lets save the build definition: buildDefinition.Save(); That’s it!

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  • An Introduction to ASP.NET Web API

    - by Rick Strahl
    Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Add Your Gmail Account to Outlook 2010 Using IMAP

    - by Mysticgeek
    If you’re upgrading from Outlook 2003 to 2010, you might want to use IMAP with your Gmail account to synchronize mail across multiple machines. Using our guide, you will be able to start using it in no time. Enable IMAP in Gmail First log into your Gmail account and open the Settings panel. Click on the Forwarding and POP/IMAP tab and verify IMAP is enabled and save changes. Next open Outlook 2010, click on the File tab to access the Backstage view. Click on Account Settings and Add and remove accounts or change existing connection settings. In the Account Settings window click on the New button. Enter in your name, email address, and password twice then click Next. Outlook will configure the email server settings, the amount of time it takes will vary. Provided everything goes correctly, the configuration will be successful and you can begin using your account. Manually Configure IMAP Settings If the above instructions don’t work, then we’ll need to manually configure the settings. Again, go into Auto Account Setup and select Manually configure server settings or additional server types and click Next.   Select Internet E-mail – Connect to POP or IMAP server to send and receive e-mail messages. Now we need to manually enter in our settings similar to the following. Under the Server Information section verify the following. Account Type: IMAP Incoming mail server: imap.gmail.com Outgoing mail server (SMTP): smtp.gmail.com Note: If you have a Google Apps account make sure to put the full email address ([email protected]) in the Your Name and User Name fields. Note: If you live outside of the US you might need to use imap.googlemail.com and smtp.googlemail.com Next, we need to click on the More Settings button… In the Internet E-mail Settings screen that pops up, click on the Outgoing Server tab, and check the box next to My outgoing server (SMTP) requires authentication. Also select the radio button next to Use same settings as my incoming mail server. In the same window click on the Advanced tab and verify the following. Incoming server: 993 Incoming server encrypted connection: SSL Outgoing server encrypted connection TLS Outgoing server: 587 Note: You will need to change the Outgoing server encrypted connection first, otherwise it will default back to port 25. Also, if TLS doesn’t work, we were able to successfully use Auto. Click OK when finished. Now we want to test the settings, before continuing on…it’s just easier that way incase something was entered incorrectly. To make sure the settings are tested, check the box Test Account Settings by clicking the Next button. If you’ve entered everything in correctly, both tasks will be completed successfully and you can close out of the window. and begin using your account via Outlook 2010. You’ll get a final congratulations message you can close out of… And begin using your account via Outlook 2010. Conclusion Using IMAP allows you to synchronize email across multiple machines and devices. The IMAP feature in Gmail is free to use, and this should get you started using it with Outlook 2010. If you’re still using 2007 or just upgraded to it, check out our guide on how to use Gmail IMAP in Outlook 2007. Similar Articles Productive Geek Tips Add Your Gmail To Windows Live MailForce Outlook 2007 to Download Complete IMAP ItemsUse Gmail IMAP in Microsoft Outlook 2007Prevent Outlook with Gmail IMAP from Showing Duplicate Tasks in the To-Do BarSetting up Gmail IMAP Support for Windows Vista Mail TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips VMware Workstation 7 Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Cool Looking Skins for Windows Media Player 12 Move the Mouse Pointer With Your Face Movement Using eViacam Boot Windows Faster With Boot Performance Diagnostics Create Ringtones For Your Android Phone With RingDroid Enhance Your Laptop’s Battery Life With These Tips Easily Search Food Recipes With Recipe Chimp

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  • SQL SERVER – History of SQL Server Database Encryption

    - by pinaldave
    I recently met Michael Coles and Rodeney Landrum the author of one of the kind book Expert SQL Server 2008 Encryption at SQLPASS in Seattle. During the conversation we ended up how Microsoft is evolving encryption technology. The same discussion lead to talking about history of encryption tools in SQL Server. Michale pointed me to page 18 of his book of encryption. He explicitly give me permission to re-produce relevant part of history from his book. Encryption in SQL Server 2000 Built-in cryptographic encryption functionality was nonexistent in SQL Server 2000 and prior versions. In order to get server-side encryption in SQL Server you had to resort to purchasing or creating your own SQL Server XPs. Creating your own cryptographic XPs could be a daunting task owing to the fact that XPs had to be compiled as native DLLs (using a language like C or C++) and the XP application programming interface (API) was poorly documented. In addition there were always concerns around creating wellbehaved XPs that “played nicely” with the SQL Server process. Encryption in SQL Server 2005 Prior to the release of SQL Server 2005 there was a flurry of regulatory activity in response to accounting scandals and attacks on repositories of confidential consumer data. Much of this regulation centered onthe need for protecting and controlling access to sensitive financial and consumer information. With the release of SQL Server 2005 Microsoft responded to the increasing demand for built-in encryption byproviding the necessary tools to encrypt data at the column level. This functionality prominently featured the following: Support for column-level encryption of data using symmetric keys or passphrases. Built-in access to a variety of symmetric and asymmetric encryption algorithms, including AES, DES, Triple DES, RC2, RC4, and RSA. Capability to create and manage symmetric keys. Key creation and management. Ability to generate asymmetric keys and self-signed certificates, or to install external asymmetric keys and certificates. Implementation of hierarchical model for encryption key management, similar to the ANSI X9.17 standard model. SQL functions to generate one-way hash codes and digital signatures, including SHA-1 and MD5 hashes. Additional SQL functions to encrypt and decrypt data. Extensions to the SQL language to support creation, use, and administration of encryption keys and certificates. SQL CLR extensions that provide access to .NET-based encryption functionality. Encryption in SQL Server 2008 Encryption demands have increased over the past few years. For instance, there has been a demand for the ability to store encryption keys “off-the-box,” physically separate from the database and the data it contains. Also there is a recognized requirement for legacy databases and applications to take advantage of encryption without changing the existing code base. To address these needs SQL Server 2008 adds the following features to its encryption arsenal: Transparent Data Encryption (TDE): Allows you to encrypt an entire database, including log files and the tempdb database, in such a way that it is transparent to client applications. Extensible Key Management (EKM): Allows you to store and manage your encryption keys on an external device known as a hardware security module (HSM). Cryptographic random number generation functionality. Additional cryptography-related catalog views and dynamic management views. SQL language extensions to support the new encryption functionality. The encryption book covers all the tools in its various chapter in one simple story. If you are interested how encryption evolved and reached to the stage where it is today, this book is must for everyone. You can read my earlier review of the book over here. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLAuthority News, T SQL, Technology Tagged: Encryption, SQL Server Encryption, SQLPASS

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  • Links to my “Best of 2010” Posts

    - by ScottGu
    I hope everyone is having a Happy New Years! 2010 has been a busy blogging year for me (this is the 100th blog post I’ve done in 2010).  Several people this week suggested I put together a summary post listing/organizing my favorite posts from the year.  Below is a quick listing of some of my favorite posts organized by topic area: VS 2010 and .NET 4 Below is a series of posts I wrote (some in late 2009) about the VS 2010 and .NET 4 (including ASP.NET 4 and WPF 4) release we shipped in April: Visual Studio 2010 and .NET 4 Released Clean Web.Config Files Starter Project Templates Multi-targeting Multiple Monitor Support New Code Focused Web Profile Option HTML / ASP.NET / JavaScript Code Snippets Auto-Start ASP.NET Applications URL Routing with ASP.NET 4 Web Forms Searching and Navigating Code in VS 2010 VS 2010 Code Intellisense Improvements WPF 4 Add Reference Dialog Improvements SEO Improvements with ASP.NET 4 Output Cache Extensibility with ASP.NET 4 Built-in Charting Controls for ASP.NET and Windows Forms Cleaner HTML Markup with ASP.NET 4 - Client IDs Optional Parameters and Named Arguments in C# 4 - and a cool scenarios with ASP.NET MVC 2 Automatic Properties, Collection Initializers and Implicit Line Continuation Support with VB 2010 New <%: %> Syntax for HTML Encoding Output using ASP.NET 4 JavaScript Intellisense Improvements with VS 2010 VS 2010 Debugger Improvements (DataTips, BreakPoints, Import/Export) Box Selection and Multi-line Editing Support with VS 2010 VS 2010 Extension Manager (and the cool new PowerCommands Extension) Pinning Projects and Solutions VS 2010 Web Deployment Debugging Tips/Tricks with Visual Studio Search and Navigation Tips/Tricks with Visual Studio Visual Studio Below are some additional Visual Studio posts I’ve done (not in the first series above) that I thought were nice: Download and Share Visual Studio Color Schemes Visual Studio 2010 Keyboard Shortcuts VS 2010 Productivity Power Tools Fun Visual Studio 2010 Wallpapers Silverlight We shipped Silverlight 4 in April, and announced Silverlight 5 the beginning of December: Silverlight 4 Released Silverlight 4 Tools for VS 2010 and WCF RIA Services Released Silverlight 4 Training Kit Silverlight PivotViewer Now Available Silverlight Questions Announcing Silverlight 5 Silverlight for Windows Phone 7 We shipped Windows Phone 7 this fall and shipped free Visual Studio development tools with great Silverlight and XNA support in September: Windows Phone 7 Developer Tools Released Building a Windows Phone 7 Twitter Application using Silverlight ASP.NET MVC We shipped ASP.NET MVC 2 in March, and started previewing ASP.NET MVC 3 this summer.  ASP.NET MVC 3 will RTM in less than 2 weeks from today: ASP.NET MVC 2: Strongly Typed Html Helpers ASP.NET MVC 2: Model Validation Introducing ASP.NET MVC 3 (Preview 1) Announcing ASP.NET MVC 3 Beta and NuGet (nee NuPack) Announcing ASP.NET MVC 3 Release Candidate 1  Announcing ASP.NET MVC 3 Release Candidate 2 Introducing Razor – A New View Engine for ASP.NET ASP.NET MVC 3: Layouts with Razor ASP.NET MVC 3: New @model keyword in Razor ASP.NET MVC 3: Server-Side Comments with Razor ASP.NET MVC 3: Razor’s @: and <text> syntax ASP.NET MVC 3: Implicit and Explicit code nuggets with Razor ASP.NET MVC 3: Layouts and Sections with Razor IIS and Web Server Stack The IIS and Web Stack teams have made a bunch of great improvements to the core web server this year: Fix Common SEO Problems using the URL Rewrite Extension Introducing the Microsoft Web Farm Framework Automating Deployment with Microsoft Web Deploy Introducing IIS Express SQL CE 4 (New Embedded Database Support with ASP.NET) Introducing Web Matrix EF Code First EF Code First is a really nice new data option that enables a very clean code-oriented data workflow: Announcing Entity Framework Code-First CTP5 Release Class-Level Model Validation with EF Code First and ASP.NET MVC 3 Code-First Development with Entity Framework 4 EF 4 Code First: Custom Database Schema Mapping Using EF Code First with an Existing Database jQuery and AJAX Contributions My team began making some significant source code contributions to the jQuery project this year: jQuery Templates, Data Link and Globalization Accepted as Official jQuery Plugins jQuery Templates and Data Linking (and Microsoft contributing to jQuery) jQuery Globalization Plugin from Microsoft Patches and Hot Fixes Some useful fixes you can download prior to VS 2010 SP1: Patch for Cut/Copy “Insufficient Memory” issue with VS 2010 Patch for VS 2010 Find and Replace Dialog Growing Patch for VS 2010 Scrolling Context Menu Videos of My Talks Some recordings of technical talks I’ve done this year: ASP.NET 4, ASP.NET MVC, and Silverlight 4 Talks I did in Europe VS 2010 and ASP.NET 4 Web Forms Talk in Arizona Other About Technical Debates (and ASP.NET Web Forms and ASP.NET MVC debates in particular) ASP.NET Security Fix Now on Windows Update Upcoming Web Camps I’d like to say a big thank you to everyone who follows my blog – I really appreciate you reading it (the comments you post help encourage me to write it).  See you in the New Year! Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • Feb 2nd Links: Visual Studio, ASP.NET, ASP.NET MVC, JQuery, Windows Phone

    - by ScottGu
    Here is the latest in my link-listing series.  Also check out my Best of 2010 Summary for links to 100+ other posts I’ve done in the last year. [I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Community News MVCConf Conference Next Wednesday: Attend the free, online ASP.NET MVC Conference being organized by the community next Wednesday.  Here is a list of some of the talks you can watch live. Visual Studio HTML5 and CSS3 in VS 2010 SP1: Good post from the Visual Studio web tools team that talks about the new support coming in VS 2010 SP1 for HTML5 and CSS3. Database Deployment with the VS 2010 Package/Publish Database Tool: Rachel Appel has a nice post that covers how to enable database deployment using the built-in VS 2010 web deployment support.  Also check out her ASP.NET web deployment post from last month. VsVim Update Released: Jared posts about the latest update of his VsVim extension for Visual Studio 2010.  This free extension enables VIM based key-bindings within VS. ASP.NET How to Add Mobile Pages to your ASP.NET Web Forms / MVC Apps: Great whitepaper by Steve Sanderson that covers how to mobile-enable your ASP.NET and ASP.NET MVC based applications. New Entity Framework Tutorials for ASP.NET Developers: The ASP.NET and EF teams have put together a bunch of nice tutorials on using the Entity Framework data library with ASP.NET Web Forms. Using ASP.NET Dynamic Data with EF Code First (via NuGet): Nice post from David Ebbo that talks about how to use the new EF Code First Library with ASP.NET Dynamic Data. Common Performance Issues with ASP.NET Web Sites: Good post with lots of performance tuning suggestions (mostly deployment settings) for ASP.NET apps. ASP.NET MVC Razor View Converter: Free, automated tool from Terlik that can convert existing .aspx view templates to Razor view templates. ASP.NET MVC 3 Internationalization: Nadeem has a great post that talks about a variety of techniques you can use to enable Globalization and Localization within your ASP.NET MVC 3 applications. ASP.NET MVC 3 Tutorials by David Hayden: Great set of tutorials and posts by David Hayden on some of the new ASP.NET MVC 3 features. EF Fixed Concurrency Mode and MVC: Chris Sells has a nice post that talks about how to handle concurrency with updates done with EF using ASP.NET MVC. ASP.NET and jQuery jQuery Performance Tips and Tricks: A free 30 minute video that covers some great tips and tricks to keep in mind when using jQuery. jQuery 1.5’s AJAX rewrite and ASP.NET services - All is well: Nice post by Dave Ward that talks about using the new jQuery 1.5 to call ASP.NET ASMX Services. Good news according to Dave is that all is well :-) jQuery UI Modal Dialogs for ASP.NET MVC: Nice post by Rob Regan that talks about a few approaches you can use to implement dialogs with jQuery UI and ASP.NET MVC.  Windows Phone 7 Free PDF eBook on Building Windows Phone 7 Applications with Silverlight: Free book that walksthrough how to use Silverlight and Visual Studio to build Windows Phone 7 applications. Hope this helps, Scott

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  • Custom ASP.Net MVC 2 ModelMetadataProvider for using custom view model attributes

    - by SeanMcAlinden
    There are a number of ways of implementing a pattern for using custom view model attributes, the following is similar to something I’m using at work which works pretty well. The classes I’m going to create are really simple: 1. Abstract base attribute 2. Custom ModelMetadata provider which will derive from the DataAnnotationsModelMetadataProvider   Base Attribute MetadataAttribute using System; using System.Web.Mvc; namespace Mvc2Templates.Attributes {     /// <summary>     /// Base class for custom MetadataAttributes.     /// </summary>     public abstract class MetadataAttribute : Attribute     {         /// <summary>         /// Method for processing custom attribute data.         /// </summary>         /// <param name="modelMetaData">A ModelMetaData instance.</param>         public abstract void Process(ModelMetadata modelMetaData);     } } As you can see, the class simple has one method – Process. Process accepts the ModelMetaData which will allow any derived custom attributes to set properties on the model meta data and add items to its AdditionalValues collection.   Custom Model Metadata Provider For a quick explanation of the Model Metadata and how it fits in to the MVC 2 framework, it is basically a set of properties that are usually set via attributes placed above properties on a view model, for example the ReadOnly and HiddenInput attributes. When EditorForModel, DisplayForModel or any of the other EditorFor/DisplayFor methods are called, the ModelMetadata information is used to determine how to display the properties. All of the information available within the model metadata is also available through ViewData.ModelMetadata. The following class derives from the DataAnnotationsModelMetadataProvider built into the mvc 2 framework. I’ve overridden the CreateMetadata method in order to process any custom attributes that may have been placed above a property in a view model.   CustomModelMetadataProvider using System; using System.Collections.Generic; using System.Linq; using System.Web.Mvc; using Mvc2Templates.Attributes; namespace Mvc2Templates.Providers {     public class CustomModelMetadataProvider : DataAnnotationsModelMetadataProvider     {         protected override ModelMetadata CreateMetadata(             IEnumerable<Attribute> attributes,             Type containerType,             Func<object> modelAccessor,             Type modelType,             string propertyName)         {             var modelMetadata = base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName);               attributes.OfType<MetadataAttribute>().ToList().ForEach(x => x.Process(modelMetadata));               return modelMetadata;         }     } } As you can see, once the model metadata is created through the base method, a check for any attributes deriving from our new abstract base attribute MetadataAttribute is made, the Process method is then called on any existing custom attributes with the model meta data for the property passed in.   Hooking it up The last thing you need to do to hook it up is set the new CustomModelMetadataProvider as the current ModelMetadataProvider, this is done within the Global.asax Application_Start method. Global.asax protected void Application_Start()         {             AreaRegistration.RegisterAllAreas();               RegisterRoutes(RouteTable.Routes);               ModelMetadataProviders.Current = new CustomModelMetadataProvider();         }   In my next post, I’m going to demonstrate a cool custom attribute that turns a textbox into an ajax driven AutoComplete text box. Hope this is useful. Kind Regards, Sean McAlinden.

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  • Some VS 2010 RC Updates (including patches for Intellisense and Web Designer fixes)

    - by ScottGu
    [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] We are continuing to make progress on shipping Visual Studio 2010.  I’d like to say a big thank you to everyone who has downloaded and tried out the VS 2010 Release Candidate, and especially to those who have sent us feedback or reported issues with it. This data has been invaluable in helping us find and fix remaining bugs before we ship the final release. Last month I blogged about a patch we released for the VS 2010 RC that fixed a bad intellisense crash issue.  This past week we released two additional patches that you can download and apply to the VS 2010 RC to immediately fix two other common issues we’ve seen people run into: Patch that fixes crashes with Tooltip invocation and when hovering over identifiers The Visual Studio team recently released a second patch that fixes some crashes we’ve seen when tooltips are displayed – most commonly when hovering over an identifier to view a QuickInfo tooltip. You can learn more about this issue from this blog post, and download and apply the patch here. Patch that fixes issues with the Web Forms designer not correctly adding controls to the auto-generated designer files The Visual Web Developer team recently released a patch that fixes issues where web controls are not correctly added to the .designer.cs file associated with the .aspx file – which means they can’t be programmed against in the code-behind file.  This issue is most commonly described as “controls are not being recognized in the code-behind” or “editing existing .aspx files regenerates the .aspx.designer.(vb or cs) file and controls are now missing” or “I can’t embed controls within the Ajax Control Toolkit TabContainer or the <asp:createuserwizard> control”. You can learn more about the issue here, and download the patch that fixes it here. Common Cause of Intellisense and IDE sluggishness on Windows XP, Vista, Win Server 2003/2008 systems Over the last few months we’ve occasionally seen reports of people seeing tremendous slowness when typing and using intellisense within VS 2010 despite running on decent machines.  It took us awhile to track down the cause – but we have found that the common culprit seems to be that these machines don’t have the latest versions of the UIA (Windows Automation) component installed. UIA 3 ships with Windows 7, and is a recommended Windows Update patch on XP and Vista (which is why we didn’t see the problem in our tests – since our machines are patched with all recommended updates).  Many systems (especially on XP) don’t automatically install recommended updates, though, and are running with older versions of UIA. This can cause significant performance slow-downs within the VS 2010 editor when large lists are displayed (for example: with intellisense). If you are running on Windows XP, Vista, or Windows Server 2003 or 2008 and are seeing any performance issues with the editor or IDE, please install the free UIA 3 update that can be downloaded from this page.  If you scroll down the page you’ll find direct links to versions for each OS. Note that we are making improvements to the final release of VS 2010 so that we don’t have big perf issues when UIA 3 isn’t installed – and we are also adding a message within the IDE that will warn you if you don’t have UIA 3 installed and accessibility is activated. Improved Text Rendering with WPF 4 and VS 2010 We recently made some nice changes to WPF 4 which improve the text clarity and text crispness over what was in the VS 2010/.NET 4 Release Candidate.  In particular these changes improve scenarios where you have a dark background with light text. You can learn more about these improvements in this WPF Team blog post.  These changes will be in the final release of VS 2010 and .NET 4. Hope this helps, Scott

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  • Visual Studio App.config XML Transformation

    - by João Angelo
    Visual Studio 2010 introduced a much-anticipated feature, Web configuration transformations. This feature allows to configure a web application project to transform the web.config file during deployment based on the current build configuration (Debug, Release, etc). If you haven’t already tried it there is a nice step-by-step introduction post to XML transformations on the Visual Web Developer Team Blog and for a quick reference on the supported syntax you have this MSDN entry. Unfortunately there are some bad news, this new feature is specific to web application projects since it resides in the Web Publishing Pipeline (WPP) and therefore is not officially supported in other project types like such as a Windows applications. The keyword here is officially because Vishal Joshi has a nice blog post on how to extend it’s support to app.config transformations. However, the proposed workaround requires that the build action for the app.config file be changed to Content instead of the default None. Also from the comments to the said post it also seems that the workaround will not work for a ClickOnce deployment. Working around this I tried to remove the build action change requirement and at the same time add ClickOnce support. This effort resulted in a single MSBuild project file (AppConfig.Transformation.targets) available for download from GitHub. It integrates itself in the build process so in order to add app.config transformation support to an existing Windows Application Project you just need to import this targets file after all the other import directives that already exist in the *.csproj file. Before – Without App.config transformation support ... <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" /> <Target Name="BeforeBuild"> </Target> <Target Name="AfterBuild"> </Target> </Project> After – With App.config transformation support ... <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" /> <Import Project="C:\MyExtensions\AppConfig.Transformation.targets" /> <Target Name="BeforeBuild"> </Target> <Target Name="AfterBuild"> </Target> </Project> As a final disclaimer, the testing time was limited so any problem that you find let me know. The MSBuild project invokes the mage tool so the Framework SDK must be installed. Update: I finally had some spare time and was able to check the problem reported by Geoff Smith and believe the problem is solved. The Publish command inside Visual Studio triggers a build workflow different than through MSBuild command line and this was causing problems. I posted a new version in GitHub that should now support ClickOnce deployment with app.config tranformation from within Visual Studio and MSBuild command line. Also here is a link for the sample application used to test the new version using the Publish command with the install location set to be from a CD-ROM or DVD-ROM and selected that the application will not check for updates. Thanks to Geoff for spotting the problem.

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  • Oracle Announces Oracle Exadata X3 Database In-Memory Machine

    - by jgelhaus
    Fourth Generation Exadata X3 Systems are Ideal for High-End OLTP, Large Data Warehouses, and Database Clouds; Eighth-Rack Configuration Offers New Low-Cost Entry Point ORACLE OPENWORLD, SAN FRANCISCO – October 1, 2012 News Facts During his opening keynote address at Oracle OpenWorld, Oracle CEO, Larry Ellison announced the Oracle Exadata X3 Database In-Memory Machine - the latest generation of its Oracle Exadata Database Machines. The Oracle Exadata X3 Database In-Memory Machine is a key component of the Oracle Cloud. Oracle Exadata X3-2 Database In-Memory Machine and Oracle Exadata X3-8 Database In-Memory Machine can store up to hundreds of Terabytes of compressed user data in Flash and RAM memory, virtually eliminating the performance overhead of reads and writes to slow disk drives, making Exadata X3 systems the ideal database platforms for the varied and unpredictable workloads of cloud computing. In order to realize the highest performance at the lowest cost, the Oracle Exadata X3 Database In-Memory Machine implements a mass memory hierarchy that automatically moves all active data into Flash and RAM memory, while keeping less active data on low-cost disks. With a new Eighth-Rack configuration, the Oracle Exadata X3-2 Database In-Memory Machine delivers a cost-effective entry point for smaller workloads, testing, development and disaster recovery systems, and is a fully redundant system that can be used with mission critical applications. Next-Generation Technologies Deliver Dramatic Performance Improvements Oracle Exadata X3 Database In-Memory Machines use a combination of scale-out servers and storage, InfiniBand networking, smart storage, PCI Flash, smart memory caching, and Hybrid Columnar Compression to deliver extreme performance and availability for all Oracle Database Workloads. Oracle Exadata X3 Database In-Memory Machine systems leverage next-generation technologies to deliver significant performance enhancements, including: Four times the Flash memory capacity of the previous generation; with up to 40 percent faster response times and 100 GB/second data scan rates. Combined with Exadata’s unique Hybrid Columnar Compression capabilities, hundreds of Terabytes of user data can now be managed entirely within Flash; 20 times more capacity for database writes through updated Exadata Smart Flash Cache software. The new Exadata Smart Flash Cache software also runs on previous generation Exadata systems, increasing their capacity for writes tenfold; 33 percent more database CPU cores in the Oracle Exadata X3-2 Database In-Memory Machine, using the latest 8-core Intel® Xeon E5-2600 series of processors; Expanded 10Gb Ethernet connectivity to the data center in the Oracle Exadata X3-2 provides 40 10Gb network ports per rack for connecting users and moving data; Up to 30 percent reduction in power and cooling. Configured for Your Business, Available Today Oracle Exadata X3-2 Database In-Memory Machine systems are available in a Full-Rack, Half-Rack, Quarter-Rack, and the new low-cost Eighth-Rack configuration to satisfy the widest range of applications. Oracle Exadata X3-8 Database In-Memory Machine systems are available in a Full-Rack configuration, and both X3 systems enable multi-rack configurations for virtually unlimited scalability. Oracle Exadata X3-2 and X3-8 Database In-Memory Machines are fully compatible with prior Exadata generations and existing systems can also be upgraded with Oracle Exadata X3-2 servers. Oracle Exadata X3 Database In-Memory Machine systems can be used immediately with any application certified with Oracle Database 11g R2 and Oracle Real Application Clusters, including SAP, Oracle Fusion Applications, Oracle’s PeopleSoft, Oracle’s Siebel CRM, the Oracle E-Business Suite, and thousands of other applications. Supporting Quotes “Forward-looking enterprises are moving towards Cloud Computing architectures,” said Andrew Mendelsohn, senior vice president, Oracle Database Server Technologies. “Oracle Exadata’s unique ability to run any database application on a fully scale-out architecture using a combination of massive memory for extreme performance and low-cost disk for high capacity delivers the ideal solution for Cloud-based database deployments today.” Supporting Resources Oracle Press Release Oracle Exadata Database Machine Oracle Exadata X3-2 Database In-Memory Machine Oracle Exadata X3-8 Database In-Memory Machine Oracle Database 11g Follow Oracle Database via Blog, Facebook and Twitter Oracle OpenWorld 2012 Oracle OpenWorld 2012 Keynotes Like Oracle OpenWorld on Facebook Follow Oracle OpenWorld on Twitter Oracle OpenWorld Blog Oracle OpenWorld on LinkedIn Mark Hurd's keynote with Andy Mendelsohn and Juan Loaiza - - watch for the replay to be available soon at http://www.youtube.com/user/Oracle or http://www.oracle.com/openworld/live/on-demand/index.html

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  • Sneak peek at next generation Three MiFi unit – Huawei E585

    - by Liam Westley
    Last Wednesday I was fortunate to be invited to a sneak preview of the next generation Three MiFi unit, the Huawei E585. Many thanks to all those who posted questions both via this blog or via @westleyl on Twitter. I think I made sure I asked every question posed to the MiFi product manager from Three UK, and so here's the answers you were after. What is a MiFi? For those who are wondering, a MiFi unit is a 3G broadband modem combined with a WiFi access point, providing 3G broadband data access to up to five devices simultaneously via standard WiFi connections. What is different? It appears the prime task of enhancing the MiFi was to improve the user experience and user interface, both in terms of the device hardware and within the management software to configure the device.  I think this was a very sensible decision as these areas had substantial room for improvement. Single button operation to switch on, enable WiFi and connect to 3G Improved OELD display (see below), replacing the multi coloured LEDs; including signal strength, SMS notifications, the number of connected clients and data usage Management is via a web based dashboard accessible from any web browser. This is a big win for those running Linux, Mac OS/X, iPad users and, for me, as I can now configure the device from Windows 7 64-bit Charging is via micro USB, the new standard for small USB devices; you cannot use your old charger for the new MiFi unit Automatic reconnection when regaining a signal Improved charging time, which should allow recharging of the device when in use Although subjective, the black and silver design does look more classy than the silver and white plastic of the original MiFi What is the same? Virtually the same size and weight The battery is the same unit as the original MiFi so you’ll have a handy spare if you upgrade Data plans remain the same as the current MiFi, so cheapest price for upgraders will be £49 pay as you go Still only works on 3G networks, with no fallback to GPRS or EDGE There is no specific upgrade path for existing three customers, either from dongle or from the original MiFi My opinion I think three have concentrated on the correct areas of usability and user experience rather than trying to add new whizz bang technology features which aren’t of interest to mainstream users. The one button operation and the improved device display will make it much easier to use when out and about. If the automatic reconnection proves reliable that will remove a major bugbear that I experienced the previous evening when travelling on the First Great Western line from Paddington to Didcot Parkway.  The signal was repeatedly lost as we sped through tunnels and cuttings, and without automatic reconnection is was a real pain to keep pressing the data button on the MiFi to re-establish my data connection. And finally, the web based dashboard will mean I no longer need to resort to my XP based netbook to configure the SSID and password. My everyday laptop runs Windows 7 64-bit which appears to confuse the older 3 WiFi manager which cannot locate the MiFi when connected. Links to other sites, and other images of the device Good first impressions from Ben Smith, http://thereallymobileproject.com/2010/06/3uk-announce-a-new-mifi-with-a-screen/ Also, a round up of other sneak preview posts, http://www.3mobilebuzz.com/2010/06/11/mifi-round-two-your-view/ Pictures Here is a comparison of the old MiFi device next to the new device, complete with OLED display and the Huawei logo now being a prominent feature on the front of the device. One of my fellow bloggers had a Linux based netbook, showing off the web based dashboard complete with Text messages panel to manage SMS. And finally, I never thought that my blog sub title would ever end up printed onto a cup cake, ... and here's some of the other cup cakes ...

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  • Oracle Support Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1)

    - by faye.todd(at)oracle.com
    Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1) Copyright (c) 2010, Oracle Corporation. All Rights Reserved. In this Document  Purpose  Last Review Date  Instructions for the Reader  Troubleshooting Details     1. Scope and Application      2. Definitions and Classifications     3. How to Use This Guide     4. Basic AQ Propagation Troubleshooting     5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages     6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment     7. Performance Issues  References Applies to: Oracle Server - Enterprise Edition - Version: 8.1.7.0 to 11.2.0.2 - Release: 8.1.7 to 11.2Information in this document applies to any platform. Purpose This document presents a step-by-step methodology for troubleshooting and resolving problems with Advanced Queuing Propagation in both Streams and basic Advanced Queuing environments. It also serves as a master reference for other more specific notes on Oracle Streams Propagation and Advanced Queuing Propagation issues. Last Review Date December 20, 2010 Instructions for the Reader A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting. Troubleshooting Details 1. Scope and Application This note is intended for Database Administrators of Oracle databases where issues are being encountered with propagating messages between advanced queues, whether the queues are used for user-created messaging systems or for Oracle Streams. It contains troubleshooting steps and links to notes for further problem resolution.It can also be used a template to document a problem when it is necessary to engage Oracle Support Services. Knowing what is NOT happening can frequently speed up the resolution process by focusing solely on the pertinent problem area. This guide is divided into five parts: Section 2: Definitions and Classifications (discusses the different types and features of propagations possible - helpful for understanding the rest of the guide) Section 3: How to Use this Guide (to be used as a start part for determining the scope of the problem and what sections to consult) Section 4. Basic AQ propagation troubleshooting (applies to both AQ propagation of user enqueued and dequeued messages as well as Oracle Streams propagations) Section 5. Additional troubleshooting steps for AQ propagation of user enqueued and dequeued messages Section 6. Additional troubleshooting steps for Oracle Streams propagation Section 7. Performance issues 2. Definitions and Classifications Given the potential scope of issues that can be encountered with AQ propagation, the first recommended step is to do some basic diagnosis to determine the type of problem that is being encountered. 2.1. What Type of Propagation is Being Used? 2.1.1. Buffered Messaging For an advanced queue, messages can be maintained on disk (persistent messaging) or in memory (buffered messaging). To determine if a queue is buffered or not, reference the GV_$BUFFERED_QUEUES view. If the queue does not appear in this view, it is persistent. 2.1.2. Propagation mode - queue-to-dblink vs queue-to-queue As of 10.2, an AQ propagation can also be defined as queue-to-dblink, or queue-to-queue: queue-to-dblink: The propagation delivers messages or events from the source queue to all subscribing queues at the destination database identified by the dblink. A single propagation schedule is used to propagate messages to all subscribing queues. Hence any changes made to this schedule will affect message delivery to all the subscribing queues. This mode does not support multiple propagations from the same source queue to the same target database. queue-to-queue: Added in 10.2, this propagation mode delivers messages or events from the source queue to a specific destination queue identified on the database link. This allows the user to have fine-grained control on the propagation schedule for message delivery. This new propagation mode also supports transparent failover when propagating to a destination Oracle RAC system. With queue-to-queue propagation, you are no longer required to re-point a database link if the owner instance of the queue fails on Oracle RAC. This mode supports multiple propagations to the same target database if the target queues are different. The default is queue-to-dblink. To verify if queue-to-queue propagation is being used, in non-Streams environments query DBA_QUEUE_SCHEDULES.DESTINATION - if a remote queue is listed along with the remote database link, then queue-to-queue propagation is being used. For Streams environments, the DBA_PROPAGATION.QUEUE_TO_QUEUE column can be checked.See the following note for a method to switch between the two modes:Document 827473.1 How to alter propagation from queue-to-queue to queue-to-dblink 2.1.3. Combined Capture and Apply (CCA) for Streams In 11g Oracle Streams environments, an optimization called Combined Capture and Apply (CCA) is implemented by default when possible. Although a propagation is configured in this case, Streams does not use it; instead it passes information directly from capture to an apply receiver. To see if CCA is in use: COLUMN CAPTURE_NAME HEADING 'Capture Name' FORMAT A30COLUMN OPTIMIZATION HEADING 'CCA Mode?' FORMAT A10SELECT CAPTURE_NAME, DECODE(OPTIMIZATION,0, 'No','Yes') OPTIMIZATIONFROM V$STREAMS_CAPTURE; Also, see the following note:Document 463820.1 Streams Combined Capture and Apply in 11g 2.2. Queue Table Compatibility There are three types of queue table compatibility. In more recent databases, queue tables may be present in all three modes of compatibility: 8.0 - earliest version, deprecated in 10.2 onwards 8.1 - support added for RAC, asynchronous notification, secure queues, queue level access control, rule-based subscribers, separate storage of history information 10.0 - if the database is in 10.1-compatible mode, then the default value for queue table compatibility is 10.0 2.3. Single vs Multiple Consumer Queue Tables If more than one recipient can dequeue a message from a queue, then its queue table is multiple consumer. You can propagate messages from a multiple-consumer queue to a single-consumer queue. Propagation from a single-consumer queue to a multiple-consumer queue is not possible. 3. How to Use This Guide 3.1. Are Messages Being Propagated at All, or is the Propagation Just Slow? Run the following query on the source database for the propagation (assuming that it is running): select TOTAL_NUMBER from DBA_QUEUE_SCHEDULES where QNAME='<source_queue_name>'; If TOTAL_NUMBER is increasing, then propagation is most likely functioning, although it may be slow. For performance issues, see Section 7. 3.2. Propagation Between Persistent User-Created Queues See Sections 4 and 5 (and optionally Section 6 if performance is an issue). 3.3. Propagation Between Buffered User-Created Queues See Sections 4, 5, and 6 (and optionally Section 7 if performance is an issue). 3.4. Propagation between Oracle Streams Queues (without Combined Capture and Apply (CCA) Optimization) See Sections 4 and 6 (and optionally Section 7 if performance is an issue). 3.5. Propagation between Oracle Streams Queues (with Combined Capture and Apply (CCA) Optimization) Although an AQ propagation is not used directly in this case, some characteristics of the message transfer are inferred from the propagation parameters used. Some parts of Sections 4 and 6 still apply. 3.6. Messaging Gateway Propagations This note does not apply to Messaging Gateway propagations. 4. Basic AQ Propagation Troubleshooting 4.1. Double-check Your Code Make sure that you are consistent in your usage of the database link(s) names, queue names, etc. It may be useful to plot a diagram of which queues are connected via which database links to make sure that the logical structure is correct. 4.2. Verify that Job Queue Processes are Running 4.2.1. Versions 10.2 and Lower - DBA_JOBS Package For versions 10.2 and lower, a scheduled propagation is managed by DBMS_JOB package. The propagation is performed by job queue process background processes. Therefore we need to verify that there are sufficient processes available for the propagation process. We should have at least 4 job queue processes running and preferably more depending on the number of other jobs running in the database. It should be noted that for AQ specific work, AQ will only ever use half of the job queue processes available.An issue caused by an inadequate job queue processes parameter setting is described in the following note:Document 298015.1 Kwqjswproc:Excep After Loop: Assigning To Self 4.2.1.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; 4.2.1.2. Job Queue Processes in Memory The following command will show how many job queue processes are currentlyin use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.1.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (spids) of job queue processes involved in propagation via select p.SPID, p.PROGRAM from V$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOBand j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%'; and these SPIDs can be used to check at the operating system level that they exist.In 8i a job queue process will have a name similar to: ora_snp1_<instance_name>.In 9i onwards you will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.2.2. Version 11.1 and Above - Oracle Scheduler In version 11.1 and above, Oracle Scheduler is used to perform AQ and Streams propagations. Oracle Scheduler automatically tunes the number of slave processes for these jobs based on the load on the computer system, and the JOB_QUEUE_PROCESSES initialization parameter is only used to specify the maximum number of slave processes. Therefore, the JOB_QUEUE_PROCESSES initialization parameter does not need to be set (it defaults to a very high number), unless you want to limit the number of slaves that can be created. If JOB_QUEUE_PROCESSES = 0, no propagation jobs will run.See the following note for a discussion of Oracle Streams 11g and Oracle Scheduler:Document 1083608.1 11g Streams and Oracle Scheduler 4.2.2.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0, and preferably be left at its default value. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; To set the JOB_QUEUE_PROCESSES parameter to its default value, run: connect / as sysdbaalter system reset JOB_QUEUE_PROCESSES; and then bounce the instance. 4.2.2.2. Job Queue Processes in Memory The following command will show how many job queue processes are currently in use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.2.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (SPIDs) of job queue processes involved in propagation via col PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_namefrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDRand jr.JOB_name=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%'; and these SPIDs can be used to check at the operating system level that they exist.You will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.3. Check the Alert Log and Any Associated Trace Files The first place to check for propagation failures is the alert logs at all sites (local and if relevant all remote sites). When a job queue process attempts to execute a schedule and fails it will always write an error stack to the alert log. This error stack will also be written in a job queue process trace file, which will be written to the BACKGROUND_DUMP_DEST location for 10.2 and below, and in the DIAGNOSTIC_DEST location for 11g. The fact that errors are written to the alert log demonstrates that the schedule is executing. This means that the problem could be with the set up of the schedule. In this example the ORA-02068 demonstrates that the failure was at the remote site. Further investigation revealed that the remote database was not open, hence the ORA-03114 error. Starting the database resolved the problem. Thu Feb 14 10:40:05 2002 Propagation Schedule for (AQADM.MULTIPLEQ, SHANE816.WORLD) encountered following error:ORA-04052: error occurred when looking up Remote object [email protected]: error occurred at recursive SQL level 4ORA-02068: following severe error from SHANE816ORA-03114: not connected to ORACLEORA-06512: at "SYS.DBMS_AQADM_SYS", line 4770ORA-06512: at "SYS.DBMS_AQADM", line 548ORA-06512: at line 1 Other potential errors that may be written to the alert log can be found in the following notes:Document 827184.1 AQ Propagation with CLOB data types Fails with ORA-22990 (11.1)Document 846297.1 AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn] (10.2, 11.1)Document 731292.1 ORA-25215 Reported on Local Propagation When Using Transformation with ANYDATA queue tables (10.2, 11.1, 11.2)Document 365093.1 ORA-07445 [kwqppay2aqe()+7360] Reported on Propagation of a Transformed Message (10.1, 10.2)Document 219416.1 Advanced Queuing Propagation Fails with ORA-22922 (9.0)Document 1203544.1 AQ Propagation Aborted with ORA-600 [ociksin: invalid status] on SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE After Upgrade (11.1, 11.2)Document 1087324.1 ORA-01405 ORA-01422 reported by Advanced Queuing Propagation schedules after RAC reconfiguration (10.2)Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370 incorrect usage of method" (9.2, 10.2, 11.1, 11.2)Document 332792.1 ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up Statspack (8.1, 9.0, 9.2, 10.1)Document 353325.1 ORA-24056: Internal inconsistency for QUEUE <queue_name> and destination <dblink> (8.1, 9.0, 9.2, 10.1, 10.2, 11.1, 11.2)Document 787367.1 ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2 (10.1, 10.2)Document 566622.1 ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1 (9.2, 10.1)Document 731539.1 ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTP (9.0, 9.2, 10.1, 10.2, 11.1)Document 253131.1 Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555) (9.2)Document 118884.1 How to unschedule a propagation schedule stuck in pending stateDocument 222992.1 DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 1204080.1 AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.Document 1233675.1 AQ Propagation stops after upgrade to 11.2.0.1 ORA-30757 4.3.1. Errors Related to Incorrect Network Configuration The most common propagation errors result from an incorrect network configuration. The list below contains common errors caused by tnsnames.ora file or database links being configured incorrectly: - ORA-12154: TNS:could not resolve service name- ORA-12505: TNS:listener does not currently know of SID given in connect descriptor- ORA-12514: TNS:listener could not resolve SERVICE_NAME - ORA-12541: TNS-12541 TNS:no listener 4.4. Check the Database Links Exist and are Functioning Correctly For schedules to remote databases confirm the database link exists via. SQL> col DBLINK for a45SQL> select QNAME, NVL(REGEXP_SUBSTR(DESTINATION, '[^@]+', 1, 2), DESTINATION) dblink2 from DBA_QUEUE_SCHEDULES3 where MESSAGE_DELIVERY_MODE = 'PERSISTENT';QNAME DBLINK------------------------------ ---------------------------------------------MY_QUEUE ORCL102B.WORLD Connect as the owner of the link and select across it to verify it works and connects to the database we expect. i.e. select * from ALL_QUEUES@ ORCL102B.WORLD; You need to ensure that the userid that scheduled the propagation (using DBMS_AQADM.SCHEDULE_PROPAGATION or DBMS_PROPAGATION_ADM.CREATE_PROPAGATION if using Streams) has access to the database link for the destination. 4.5. Has Propagation Been Correctly Scheduled? Check that the propagation schedule has been created and that a job queue process has been assigned. Look for the entry in DBA_QUEUE_SCHEDULES and SYS.AQ$_SCHEDULES for your schedule. For 10g and below, check that it has a JOBNO entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_JOBS with that JOBNO. For 11g and above, check that the schedule has a JOB_NAME entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_SCHEDULER_JOBS with that JOB_NAME. Check the destination is as intended and spelled correctly. SQL> select SCHEMA, QNAME, DESTINATION, SCHEDULE_DISABLED, PROCESS_NAME from DBA_QUEUE_SCHEDULES;SCHEMA QNAME DESTINATION S PROCESS------- ---------- ------------------ - -----------AQADM MULTIPLEQ AQ$_LOCAL N J000 AQ$_LOCAL in the destination column shows that the queue to which we are propagating to is in the same database as the source queue. If the propagation was to a remote (different) database, a database link will be in the DESTINATION column. The entry in the SCHEDULE_DISABLED column, N, means that the schedule is NOT disabled. If Y (yes) appears in this column, propagation is disabled and the schedule will not be executed. If not using Oracle Streams, propagation should resume once you have enabled the schedule by invoking DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE (for 10.2 Oracle Streams and above, the DBMS_PROPAGATION_ADM.START_PROPAGATION procedure should be used). The PROCESS_NAME is the name of the job queue process currently allocated to execute the schedule. This process is allocated dynamically at execution time. If the PROCESS_NAME column is null (empty) the schedule is not currently executing. You may need to execute this statement a number of times to verify if a process is being allocated. If a process is at some time allocated to the schedule, it is attempting to execute. SQL> select SCHEMA, QNAME, LAST_RUN_DATE, NEXT_RUN_DATE from DBA_QUEUE_SCHEDULES;SCHEMA QNAME LAST_RUN_DATE NEXT_RUN_DATE------ ----- ----------------------- ----------------------- AQADM MULTIPLEQ 13-FEB-2002 13:18:57 13-FEB-2002 13:20:30 In 11g, these dates are expressed in TIMESTAMP WITH TIME ZONE datatypes. If the NEXT_RUN_DATE and NEXT_RUN_TIME columns are null when this statement is executed, the scheduled propagation is currently in progress. If they never change it would suggest that the schedule itself is never executing. If the next scheduled execution is too far away, change the NEXT_TIME parameter of the schedule so that schedules are executed more frequently (assuming that the window is not set to be infinite). Parameters of a schedule can be changed using the DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE call. In 10g and below, scheduling propagation posts a job in the DBA_JOBS view. The columns are more or less the same as DBA_QUEUE_SCHEDULES so you just need to recognize the job and verify that it exists. SQL> select JOB, WHAT from DBA_JOBS where WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';JOB WHAT---- ----------------- 720 next_date := sys.dbms_aqadm.aq$_propaq(job); For 11g, scheduling propagation posts a job in DBA_SCHEDULER_JOBS instead: SQL> select JOB_NAME from DBA_SCHEDULER_JOBS where JOB_NAME like 'AQ_JOB$_%';JOB_NAME------------------------------AQ_JOB$_41 If no job exists, check DBA_QUEUE_SCHEDULES to make sure that the schedule has not been disabled. For 10g and below, the job number is dynamic for AQ propagation schedules. The procedure that is executed to expedite a propagation schedule runs, removes itself from DBA_JOBS, and then reposts a new job for the next scheduled propagation. The job number should therefore always increment unless the schedule has been set up to run indefinitely. 4.6. Is the Schedule Executing but Failing to Complete? Run the following query: SQL> select FAILURES, LAST_ERROR_MSG from DBA_QUEUE_SCHEDULES;FAILURES LAST_ERROR_MSG------------ -----------------------1 ORA-25207: enqueue failed, queue AQADM.INQ is disabled from enqueueingORA-02063: preceding line from SHANE816 The failures column shows how many times we have attempted to execute the schedule and failed. Oracle will attempt to execute the schedule 16 times after which it will be removed from the DBA_JOBS or DBA_SCHEDULER_JOBS view and the schedule will become disabled. The column DBA_QUEUE_SCHEDULES.SCHEDULE_DISABLED will show 'Y'. For 11g and above, the DBA_SCHEDULER_JOBS.STATE column will show 'BROKEN' for the job corresponding to DBA_QUEUE_SCHEDULES.JOB_NAME. Prior to 10g the back off algorithm for failures was exponential, whereas from 10g onwards it is linear. The propagation will become disabled on the 17th attempt. Only the last execution failure will be reflected in the LAST_ERROR_MSG column. That is, if the schedule fails 5 times for 5 different reasons, only the last set of errors will be recorded in DBA_QUEUE_SCHEDULES. Any errors need to be resolved to allow propagation to continue. If propagation has also become disabled due to 17 failures, first resolve the reason for the error and then re-enable the schedule using the DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE procedure, or DBMS_PROPAGATION_ADM.START_PROPAGATION if using 10.2 or above Oracle Streams. As soon as the schedule executes successfully the error message entries will be deleted. Oracle does not keep a history of past failures. However, when using Oracle Streams, the errors will be retained in the DBA_PROPAGATION view even after the schedule resumes successfully. See the following note for instructions on how to clear out the errors from the DBA_PROPAGATION view:Document 808136.1 How to clear the old errors from DBA_PROPAGATION view?If a schedule is active and no errors are being reported then the source queue may not have any messages to be propagated. 4.7. Do the Propagation Notification Queue Table and Queue Exist? Check to see that the propagation notification queue table and queue exist and are enabled for enqueue and dequeue. Propagation makes use of the propagation notification queue for handling propagation run-time events, and the messages in this queue are stored in a SYS-owned queue table. This queue should never be stopped or dropped and the corresponding queue table never be dropped. 10g and belowThe propagation notification queue table is of the format SYS.AQ$_PROP_TABLE_n, where 'n' is the RAC instance number, i.e. '1' for a non-RAC environment. This queue and queue table are created implicitly when propagation is first scheduled. If propagation has been scheduled and these objects do not exist, try unscheduling and rescheduling propagation. If they still do not exist contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ$_PROP_TABLE_1SQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ$_PROP_NOTIFY_1 YES YESAQ$_AQ$_PROP_TABLE_1_E NO NO If the AQ$_PROP_NOTIFY_1 queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_1_E should not be enabled for enqueue or dequeue.11g and aboveThe propagation notification queue table is of the format SYS.AQ_PROP_TABLE, and is created when the database is created. If they do not exist, contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ_PROP_TABLESQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ_PROP_NOTIFY YES YESAQ$_AQ_PROP_TABLE_E NO NO If the AQ_PROP_NOTIFY queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_E should not be enabled for enqueue or dequeue. 4.8. Does the Remote Queue Exist and is it Enabled for Enqueueing? Check that the remote queue the propagation is transferring messages to exists and is enabled for enqueue: SQL> select DESTINATION from USER_QUEUE_SCHEDULES where QNAME = 'OUTQ';DESTINATION-----------------------------------------------------------------------------"AQADM"."INQ"@M2V102.ESSQL> select OWNER, NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED from [email protected];OWNER NAME ENQUEUE DEQUEUE-------- ------ ----------- -----------AQADM INQ YES YES 4.9. Do the Target and Source Database Charactersets Differ? If a message fails to propagate, check the database charactersets of the source and target databases. Investigate whether the same message can propagate between the databases with the same characterset or it is only a particular combination of charactersets which causes a problem. 4.10. Check the Queue Table Type Agreement Propagation is not possible between queue tables which have types that differ in some respect. One way to determine if this is the case is to run the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure for the two queues that the propagation operates on. If the types do not agree, DBMS_AQADM.VERIFY_QUEUE_TYPES will return '0'.For AQ propagation between databases which have different NLS_LENGTH_SEMANTICS settings, propagation will not work, unless the queues are Oracle Streams ANYDATA queues.See the following notes for issues caused by lack of type agreement:Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 353754.1 Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT 4.11. Enable Propagation Tracing 4.11.1. System Level This is set it in the init.ora/spfile as follows: event="24040 trace name context forever, level 10" and restart the instanceThis event cannot be set dynamically with an alter system command until version 10.2: SQL> alter system set events '24040 trace name context forever, level 10'; To unset the event: SQL> alter system set events '24040 trace name context off'; Debugging information will be logged to job queue trace file(s) (jnnn) as propagation takes place. You can check the trace file for errors, and for statements indicating that messages have been sent. For the most part the trace information is understandable. This trace should also be uploaded to Oracle Support if a service request is created. 4.11.2. Attaching to a Specific Process We can also attach to an existing job queue processes that is running a propagation schedule and trace it individually using the oradebug utility, as follows:10.2 and below connect / as sysdbaselect p.SPID, p.PROGRAM from v$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 11g connect / as sysdbacol PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_NAMEfrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 4.11.3. Further Tracing The previous tracing steps only trace the job queue process executing the propagation on the source. At times it is useful to trace the propagation receiver process (the session which is enqueueing the messages into the target queue) on the target database which is associated with the job queue process on the source database.These following queries provide ways of identifying the processes involved in propagation so that you can attach to them via oradebug to generate trace information.In order to identify the propagation receiver process you need to execute the query as a user with privileges to access the v$ views in both the local and remote databases so the database link must connect as a user with those privileges in the remote database. The <DBLINK> in the queries should be replaced by the appropriate database link.The queries have two forms due to the differences between operating systems. The value returned by 'Rem Process' is the operating system identifier of the propagation receiver on the remote database. Once identified, this process can be attached to and traced on the remote database using the commands given in Section 4.11.2.10.2 and below - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from v$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 10.2 and below - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=sr.PROCESS; 11g - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 11g - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=sr.PROCESS;   5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages 5.1. Check the Privileges of All Users Involved Ensure that the owner of the database link has the necessary privileges on the aq packages. SQL> select TABLE_NAME, PRIVILEGE from USER_TAB_PRIVS;TABLE_NAME PRIVILEGE------------------------------ ----------------------------------------DBMS_LOCK EXECUTEDBMS_AQ EXECUTEDBMS_AQADM EXECUTEDBMS_AQ_BQVIEW EXECUTEQT52814_BUFFER SELECT Note that when queue table is created, a view called QT<nnn>_BUFFER is created in the SYS schema, and the queue table owner is given SELECT privileges on it. The <nnn> corresponds to the object_id of the associated queue table. SQL> select * from USER_ROLE_PRIVS;USERNAME GRANTED_ROLE ADM DEF OS_------------------------------ ------------------------------ ---- ---- ---AQ_USER1 AQ_ADMINISTRATOR_ROLE NO YES NOAQ_USER1 CONNECT NO YES NOAQ_USER1 RESOURCE NO YES NO It is good practice to configure central AQ administrative user. All admin and processing jobs are created, executed and administered as this user. This configuration is not mandatory however, and the database link can be owned by any existing queue user. If this latter configuration is used, ensure that the connecting user has the necessary privileges on the AQ packages and objects involved. Privileges for an AQ Administrative user Execute on DBMS_AQADM Execute on DBMS_AQ Granted the AQ_ADMINISTRATOR_ROLE Privileges for an AQ user Execute on DBMS_AQ Execute on the message payload Enqueue privileges on the remote queue Dequeue privileges on the originating queue Privileges need to be confirmed on both sites when propagation is scheduled to remote destinations. Verify that the user ID used to login to the destination through the database link has been granted privileges to use AQ. 5.2. Verify Queue Payload Types AQ will not propagate messages from one queue to another if the payload types of the two queues are not verified to be equivalent. An AQ administrator can verify if the source and destination's payload types match by executing the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure. The results of the type checking will be stored in the SYS.AQ$_MESSAGE_TYPES table. This table can be accessed using the object identifier OID of the source queue and the address database link of the destination queue, i.e. [schema.]queue_name[@destination]. Prior to Oracle 9i the payload (message type) had to be the same for all the queue tables involved in propagation. From Oracle9i onwards a transformation can be used so that payloads can be converted from one type to another. The following procedural call made on the source database can verify whether we can propagate between the source and the destination queue tables. connect aq_user1/[email protected] serverout onDECLARErc_value number;BEGINDBMS_AQADM.VERIFY_QUEUE_TYPES(src_queue_name => 'AQ_USER1.Q_1', dest_queue_name => 'AQ_USER2.Q_2',destination => 'dbl_aq_user2.es',rc => rc_value);dbms_output.put_line('rc_value code is '||rc_value);END;/ If propagation is possible then the return code value will be 1. If it is 0 then propagation is not possible and further investigation of the types and transformations used by and in conjunction with the queue tables is required. With regard to comparison of the types the following sql can be used to extract the DDL for a specific type with' %' changed appropriately on the source and target. This can then be compared for the source and target. SET LONG 20000 set pagesize 50 EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'STORAGE',false); SELECT DBMS_METADATA.GET_DDL('TYPE',t.type_name) from user_types t WHERE t.type_name like '%'; EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'DEFAULT'); 5.3. Check Message State and Destination The first step in this process is to identify the queue table associated with the problem source queue. Although you schedule propagation for a specific queue, most of the meta-data associated with that queue is stored in the underlying queue table. The following statement finds the queue table for a given queue (note that this is a multiple-consumer queue table). SQL> select QUEUE_TABLE from DBA_QUEUES where NAME = 'MULTIPLEQ';QUEUE_TABLE --------------------MULTIPLEQTABLE For a small amount of messages in a multiple-consumer queue table, the following query can be run: SQL> select MSG_STATE, CONSUMER_NAME, ADDRESS from AQ$MULTIPLEQTABLE where QUEUE = 'MULTIPLEQ';MSG_STATE CONSUMER_NAME ADDRESS-------------- ----------------------- -------------READY AQUSER2 [email protected] AQUSER1READY AQUSER3 AQADM.INQ In this example we see 2 messages ready to be propagated to remote queues and 1 that is not. If the address column is blank, the message is not scheduled for propagation and can only be dequeued from the queue upon which it was enqueued. The MSG_STATE column values are discussed in Document 102330.1 Advanced Queueing MSG_STATE Values and their Interpretation. If the address column has a value, the message has been enqueued for propagation to another queue. The first row in the example includes a database link (@M2V102.ES). This demonstrates that the message should be propagated to a queue at a remote database. The third row does not include a database link so will be propagated to a queue that resides on the same database as the source queue. The consumer name is the intended recipient at the target queue. Note that we are not querying the base queue table directly; rather, we are querying a view that is available on top of every queue table, AQ$<queue_table_name>.A more realistic query in an environment where the queue table contains thousands of messages is8.0.3-compatible multiple-consumer queue table and all compatibility single-consumer queue tables select count(*), MSG_STATE, QUEUE from AQ$<queue_table_name>  group by MSG_STATE, QUEUE; 8.1.3 and 10.0-compatible queue tables select count(*), MSG_STATE, QUEUE, CONSUMER_NAME from AQ$<queue_table_name>group by MSG_STATE, QUEUE, CONSUMER_NAME; For multiple-consumer queue tables, if you did not see the expected CONSUMER_NAME , check the syntax of the enqueue code and verify the recipients are declared correctly. If a recipients list is not used on enqueue, check the subscriber list in the AQ$_<queue_table_name>_S view (note that a single-consumer queue table does not have a subscriber view. This view records all members of the default subscription list which were added using the DBMS_AQADM.ADD_SUBSCRIBER procedure and also those enqueued using a recipient list. SQL> select QUEUE, NAME, ADDRESS from AQ$MULTIPLEQTABLE_S;QUEUE NAME ADDRESS---------- ----------- -------------MULTIPLEQ AQUSER2 [email protected] AQUSER1 In this example we have 2 subscribers registered with the queue. We have a local subscriber AQUSER1, and a remote subscriber AQUSER2, on the queue INQ, owned by AQADM, at M2V102.ES. Unless overridden with a recipient list during enqueue every message enqueued to this queue will be propagated to INQ at M2V102.ES.For 8.1 style and above multiple consumer queue tables, you can also check the following information at the target: select CONSUMER_NAME, DEQ_TXN_ID, DEQ_TIME, DEQ_USER_ID, PROPAGATED_MSGID from AQ$<queue_table_name> where QUEUE = '<QUEUE_NAME>'; For 8.0 style queues, if the queue table supports multiple consumers you can obtain the same information from the history column of the queue table: select h.CONSUMER, h.TRANSACTION_ID, h.DEQ_TIME, h.DEQ_USER, h.PROPAGATED_MSGIDfrom AQ$<queue_table_name> t, table(t.history) h where t.Q_NAME = '<QUEUE_NAME>'; A non-NULL TRANSACTION_ID indicates that the message was successfully propagated. Further, the DEQ_TIME indicates the time of propagation, the DEQ_USER indicates the userid used for propagation, and the PROPAGATED_MSGID indicates the message ID of the message that was enqueued at the destination. 6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment 6.1. Is the Propagation Enabled? For a propagation job to propagate messages, the propagation must be enabled. For Streams, a special view called DBA_PROPAGATION exists to convey information about Streams propagations. If messages are not being propagated by a propagation as expected, then the propagation might not be enabled. To query for this: SELECT p.PROPAGATION_NAME, DECODE(s.SCHEDULE_DISABLED, 'Y', 'Disabled','N', 'Enabled') SCHEDULE_DISABLED, s.PROCESS_NAME, s.FAILURES, s.LAST_ERROR_MSGFROM DBA_QUEUE_SCHEDULES s, DBA_PROPAGATION pWHERE p.DESTINATION_DBLINK = NVL(REGEXP_SUBSTR(s.DESTINATION, '[^@]+', 1, 2), s.DESTINATION) AND s.SCHEMA = p.SOURCE_QUEUE_OWNER AND s.QNAME = p.SOURCE_QUEUE_NAME AND MESSAGE_DELIVERY_MODE = 'PERSISTENT' order by PROPAGATION_NAME; At times, the propagation job may become "broken" or fail to start after an error has been encountered or after a database restart. If an error is indicated by the above query, an attempt to disable the propagation and then re-enable it can be made. In the examples below, for the propagation named STRMADMIN_PROPAGATE where the queue name is STREAMS_QUEUE owned by STRMADMIN and the destination database link is ORCL2.WORLD, the commands would be:10.2 and above exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE'); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); If the above does not fix the problem, stop the propagation specifying the force parameter (2nd parameter on stop_propagation) as TRUE: exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE',true); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); The statistics for the propagation as well as any old error messages are cleared when the force parameter is set to TRUE. Therefore if the propagation schedule is stopped with FORCE set to TRUE, and upon restart there is still an error message in DBA_PROPAGATION, then the error message is current.9.2 or 10.1 exec dbms_aqadm.disable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms.aqadm.enable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); If the above does not fix the problem, perform an unschedule of propagation and then schedule_propagation: exec dbms_aqadm.unschedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms_aqadm.schedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); Typically if the error from the first query in Section 6.1 recurs after restarting the propagation as shown above, further troubleshooting of the error is needed. 6.2. Check Propagation Rule Sets and Transformations Inspect the configuration of the rules in the rule set that is associated with the propagation process to make sure that they evaluate to TRUE as expected. If not, then the object or schema will not be propagated. Remember that when a negative rule evaluates to TRUE, the specified object or schema will not be propagated. Finally inspect any rule-based transformations that are implemented with propagation to make sure they are changing the data in the intended way.The following query shows what rule sets are assigned to a propagation: select PROPAGATION_NAME, RULE_SET_OWNER||'.'||RULE_SET_NAME "Positive Rule Set",NEGATIVE_RULE_SET_OWNER||'.'||NEGATIVE_RULE_SET_NAME "Negative Rule Set"from DBA_PROPAGATION; The next two queries list the propagation rules and their conditions. The first is for the positive rule set, the second is for the negative rule set: set long 4000select rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES rwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER and RULE_SET_NAME in(select RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME;   set long 4000select c.PROPAGATION_NAME, rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES r ,DBA_PROPAGATION cwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER andrsr.RULE_SET_OWNER=c.NEGATIVE_RULE_SET_OWNER and rsr.RULE_SET_NAME=c.NEGATIVE_RULE_SET_NAMEand rsr.RULE_SET_NAME in(select NEGATIVE_RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME; 6.3. Determining the Total Number of Messages and Bytes Propagated As in Section 3.1, determining if messages are flowing can be instructive to see whether the propagation is entirely hung or just slow. If the propagation is not in flow control (see Section 6.5.2), but the statistics are incrementing slowly, there may be a performance issue. For Streams implementations two views are available that can assist with this that can show the number of messages sent by a propagation, as well as the number of acknowledgements being returned from the target site: the V$PROPAGATION_SENDER view at the Source site and the V$PROPAGATION_RECEIVER view at the destination site. It is helpful to query both to determine if messages are being delivered to the target. Look for the statistics to increase.Source: select QUEUE_SCHEMA, QUEUE_NAME, DBLINK,HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS, TOTAL_BYTESfrom V$PROPAGATION_SENDER; Target: select SRC_QUEUE_SCHEMA, SRC_QUEUE_NAME, SRC_DBNAME, DST_QUEUE_SCHEMA, DST_QUEUE_NAME, HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS from V$PROPAGATION_RECEIVER; 6.4. Check Buffered Subscribers The V$BUFFERED_SUBSCRIBERS view displays information about subscribers for all buffered queues in the instance. This view can be queried to make sure that the site that the propagation is propagating to is listed as a subscriber address for the site being propagated from: select QUEUE_SCHEMA, QUEUE_NAME, SUBSCRIBER_ADDRESS from V$BUFFERED_SUBSCRIBERS; The SUBSCRIBER_ADDRESS column will not be populated when the propagation is local (between queues on the same database). 6.5. Common Streams Propagation Errors 6.5.1. ORA-02082: A loopback database link must have a connection qualifier. This error can occur if you use the Streams Setup Wizard in Oracle Enterprise Manager without first configuring the GLOBAL_NAME for your database. 6.5.2. ORA-25307: Enqueue rate too high. Enable flow control DBA_QUEUE_SCHEDULES will display this informational message for propagation when the automatic flow control (10g feature of Streams) has been invoked.Similar to Streams capture processes, a Streams propagation process can also go into a state of 'flow control. This is an informative message that indicates flow control has been automatically enabled to reduce the rate at which messages are being enqueued into at target queue.This typically occurs when the target site is unable to keep up with the rate of messages flowing from the source site. Other than checking that the apply process is running normally on the target site, usually no action is required by the DBA. Propagation and the capture process will be resumed automatically when the target site is able to accept more messages.The following document contains more information:Document 302109.1 Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlSee the following document for one potential cause of this situation:Document 1097115.1 Oracle Streams Apply Reader is in 'Paused' State 6.5.3. ORA-25315 unsupported configuration for propagation of buffered messages This error typically occurs when the target database is RAC and usually indicates that an attempt was made to propagate buffered messages with the database link pointing to an instance in the destination database which is not the owner instance of the destination queue. To resolve the problem, use queue-to-queue propagation for buffered messages. 6.5.4. ORA-600 [KWQBMCRCPTS101] after dropping / recreating propagation For cause/fixes refer to:Document 421237.1 ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams Propagation 6.5.5. Stopping or Dropping a Streams Propagation Hangs See the following note:Document 1159787.1 Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It Hang 6.6. Streams Propagation-Related Notes for Common Issues Document 437838.1 Streams Specific PatchesDocument 749181.1 How to Recover Streams After Dropping PropagationDocument 368912.1 Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentDocument 564649.1 ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveDocument 553017.1 Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201Document 944846.1 Streams Propagation Fails Ora-7445 [kohrsmc]Document 745601.1 ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'Document 333068.1 ORA-23603: Streams Enqueue Aborted Eue To Low SGADocument 363496.1 Ora-25315 Propagating on RAC StreamsDocument 368237.1 Unable to Unschedule Propagation. Streams Queue is InvalidDocument 436332.1 dbms_propagation_adm.stop_propagation hangsDocument 727389.1 Propagation Fails With ORA-12528Document 730911.1 ORA-4063 Is Reported After Dropping Negative Prop.RulesetDocument 460471.1 Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsDocument 1165583.1 ORA-600 [kwqpuspse0-ack] In Streams EnvironmentDocument 1059029.1 Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationDocument 556309.1 Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedDocument 839568.1 Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''Document 311021.1 Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredDocument 359971.1 STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068Document 1101616.1 DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747 7. Performance Issues A propagation may seem to be slow if the queries from Sections 3.1 and 6.3 show that the message statistics are not changing quickly. In Oracle Streams, this more usually is due to a slow apply process at the target rather than a slow propagation. Propagation could be inferred to be slow if the message statistics are changing, and the state of a capture process according to V$STREAMS_CAPTURE.STATE is PAUSED FOR FLOW CONTROL, but an ORA-25307 'Enqueue rate too high. Enable flow control' warning is NOT observed in DBA_QUEUE_SCHEDULES per Section 6.5.2. If this is the case, see the following notes / white papers for suggestions to increase performance:Document 335516.1 Master Note for Streams Performance RecommendationsDocument 730036.1 Overview for Troubleshooting Streams Performance IssuesDocument 780733.1 Streams Propagation Tuning with Network ParametersWhite Paper: http://www.oracle.com/technetwork/database/features/availability/maa-wp-10gr2-streams-performance-130059.pdfWhite Paper: Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2, http://www.oracle.com/technetwork/database/features/availability/maa-10gr2-streams-configuration-132039.pdf, See APPENDIX A: USING STREAMS CONFIGURATIONS OVER A NETWORKFor basic AQ propagation, the network tuning in the aforementioned Appendix A of the white paper 'Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2' is applicable. References NOTE:102330.1 - Advanced Queueing MSG_STATE Values and their InterpretationNOTE:102771.1 - Advanced Queueing Propagation using PL/SQLNOTE:1059029.1 - Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationNOTE:1079577.1 - Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"NOTE:1083608.1 - 11g Streams and Oracle SchedulerNOTE:1087324.1 - ORA-01405 ORA-01422 reported by Adavanced Queueing Propagation schedules after RAC reconfigurationNOTE:1097115.1 - Oracle Streams Apply Reader is in 'Paused' StateNOTE:1101616.1 - DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747NOTE:1159787.1 - Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It HangNOTE:1165583.1 - ORA-600 [kwqpuspse0-ack] In Streams EnvironmentNOTE:118884.1 - How to unschedule a propagation schedule stuck in pending stateNOTE:1203544.1 - AQ PROPAGATION ABORTED WITH ORA-600[OCIKSIN: INVALID STATUS] ON SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE AFTER UPGRADENOTE:1204080.1 - AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.NOTE:219416.1 - Advanced Queuing Propagation fails with ORA-22922NOTE:222992.1 - DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082NOTE:253131.1 - Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555)NOTE:282987.1 - Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueNOTE:298015.1 - Kwqjswproc:Excep After Loop: Assigning To SelfNOTE:302109.1 - Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlNOTE:311021.1 - Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredNOTE:332792.1 - ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up StatspackNOTE:333068.1 - ORA-23603: Streams Enqueue Aborted Eue To Low SGANOTE:335516.1 - Master Note for Streams Performance RecommendationsNOTE:353325.1 - ORA-24056: Internal inconsistency for QUEUE and destination NOTE:353754.1 - Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT.NOTE:359971.1 - STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068NOTE:363496.1 - Ora-25315 Propagating on RAC StreamsNOTE:365093.1 - ORA-07445 [kwqppay2aqe()+7360] reported on Propagation of a Transformed MessageNOTE:368237.1 - Unable to Unschedule Propagation. Streams Queue is InvalidNOTE:368912.1 - Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentNOTE:421237.1 - ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams PropagationNOTE:436332.1 - dbms_propagation_adm.stop_propagation hangsNOTE:437838.1 - Streams Specific PatchesNOTE:460471.1 - Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsNOTE:463820.1 - Streams Combined Capture and Apply in 11gNOTE:553017.1 - Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201NOTE:556309.1 - Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedNOTE:564649.1 - ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveNOTE:566622.1 - ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1NOTE:727389.1 - Propagation Fails With ORA-12528NOTE:730036.1 - Overview for Troubleshooting Streams Performance IssuesNOTE:730911.1 - ORA-4063 Is Reported After Dropping Negative Prop.RulesetNOTE:731292.1 - ORA-25215 Reported On Local Propagation When Using Transformation with ANYDATA queue tablesNOTE:731539.1 - ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTPNOTE:745601.1 - ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'NOTE:749181.1 - How to Recover Streams After Dropping PropagationNOTE:780733.1 - Streams Propagation Tuning with Network ParametersNOTE:787367.1 - ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2NOTE:808136.1 - How to clear the old errors from DBA_PROPAGATION view ?NOTE:827184.1 - AQ Propagation with CLOB data types Fails with ORA-22990NOTE:827473.1 - How to alter propagation from queue_to_queue to queue_to_dblinkNOTE:839568.1 - Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''NOTE:846297.1 - AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn]NOTE:944846.1 - Streams Propagation Fails Ora-7445 [kohrsmc]

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  • Write, Read and Update Oracle CLOBs with PL/SQL

    - by robertphyatt
    Fun with CLOBS! If you are using Oracle, if you have to deal with text that is over 4000 bytes, you will probably find yourself dealing with CLOBs, which can go up to 4GB. They are pretty tricky, and it took me a long time to figure out these lessons learned. I hope they will help some down-trodden developer out there somehow. Here is my original code, which worked great on my Oracle Express Edition: (for all examples, the first one writes a new CLOB, the next one Updates an existing CLOB and the final one reads a CLOB back) CREATE OR REPLACE PROCEDURE PRC_WR_CLOB (        p_document      IN VARCHAR2,        p_id            OUT NUMBER) IS      lob_loc CLOB; BEGIN    INSERT INTO TBL_CLOBHOLDERDDOC (CLOBHOLDERDDOC)        VALUES (empty_CLOB())        RETURNING CLOBHOLDERDDOC, CLOBHOLDERDDOCID INTO lob_loc, p_id;    DBMS_LOB.WRITE(lob_loc, LENGTH(UTL_RAW.CAST_TO_RAW(p_document)), 1, UTL_RAW.CAST_TO_RAW(p_document)); END; / CREATE OR REPLACE PROCEDURE PRC_UD_CLOB (        p_document      IN VARCHAR2,        p_id            IN NUMBER) IS      lob_loc CLOB; BEGIN        SELECT CLOBHOLDERDDOC INTO lob_loc FROM TBL_CLOBHOLDERDDOC        WHERE CLOBHOLDERDDOCID = p_id FOR UPDATE;    DBMS_LOB.WRITE(lob_loc, LENGTH(UTL_RAW.CAST_TO_RAW(p_document)), 1, UTL_RAW.CAST_TO_RAW(p_document)); END; / CREATE OR REPLACE PROCEDURE PRC_RD_CLOB (    p_id IN NUMBER,    p_clob OUT VARCHAR2) IS    lob_loc  CLOB; BEGIN    SELECT CLOBHOLDERDDOC INTO lob_loc    FROM   TBL_CLOBHOLDERDDOC    WHERE  CLOBHOLDERDDOCID = p_id;    p_clob := UTL_RAW.CAST_TO_VARCHAR2(DBMS_LOB.SUBSTR(lob_loc, DBMS_LOB.GETLENGTH(lob_loc), 1)); END; / As you can see, I had originally been casting everything back and forth between RAW formats using the UTL_RAW.CAST_TO_VARCHAR2() and UTL_RAW.CAST_TO_RAW() functions all over the place, but it had the nasty side effect of working great on my Oracle express edition on my developer box, but having all the CLOBs above a certain size display garbage when read back on the Oracle test database server . So...I kept working at it and came up with the following, which ALSO worked on my Oracle Express Edition on my developer box:   CREATE OR REPLACE PROCEDURE PRC_WR_CLOB (     p_document      IN VARCHAR2,     p_id        OUT NUMBER) IS       lob_loc CLOB; BEGIN     INSERT INTO TBL_CLOBHOLDERDOC (CLOBHOLDERDOC)         VALUES (empty_CLOB())         RETURNING CLOBHOLDERDOC, CLOBHOLDERDOCID INTO lob_loc, p_id;     DBMS_LOB.WRITE(lob_loc, LENGTH(p_document), 1, p_document);   END; / CREATE OR REPLACE PROCEDURE PRC_UD_CLOB (     p_document      IN VARCHAR2,     p_id        IN NUMBER) IS       lob_loc CLOB; BEGIN     SELECT CLOBHOLDERDOC INTO lob_loc FROM TBL_CLOBHOLDERDOC     WHERE CLOBHOLDERDOCID = p_id FOR UPDATE;     DBMS_LOB.WRITE(lob_loc, LENGTH(p_document), 1, p_document); END; / CREATE OR REPLACE PROCEDURE PRC_RD_CLOB (     p_id IN NUMBER,     p_clob OUT VARCHAR2) IS     lob_loc  CLOB; BEGIN     SELECT CLOBHOLDERDOC INTO lob_loc     FROM   TBL_CLOBHOLDERDOC     WHERE  CLOBHOLDERDOCID = p_id;     p_clob := DBMS_LOB.SUBSTR(lob_loc, DBMS_LOB.GETLENGTH(lob_loc), 1); END; / Unfortunately, by changing my code to what you see above, even though it kept working on my Oracle express edition, everything over a certain size just started truncating after about 7950 characters on the test server! Here is what I came up with in the end, which is actually the simplest solution and this time worked on both my express edition and on the database server (note that only the read function was changed to fix the truncation issue, and that I had Oracle worry about converting the CLOB into a VARCHAR2 internally): CREATE OR REPLACE PROCEDURE PRC_WR_CLOB (        p_document      IN VARCHAR2,        p_id            OUT NUMBER) IS      lob_loc CLOB; BEGIN    INSERT INTO TBL_CLOBHOLDERDDOC (CLOBHOLDERDDOC)        VALUES (empty_CLOB())        RETURNING CLOBHOLDERDDOC, CLOBHOLDERDDOCID INTO lob_loc, p_id;    DBMS_LOB.WRITE(lob_loc, LENGTH(p_document), 1, p_document); END; / CREATE OR REPLACE PROCEDURE PRC_UD_CLOB (        p_document      IN VARCHAR2,        p_id            IN NUMBER) IS      lob_loc CLOB; BEGIN        SELECT CLOBHOLDERDDOC INTO lob_loc FROM TBL_CLOBHOLDERDDOC        WHERE CLOBHOLDERDDOCID = p_id FOR UPDATE;    DBMS_LOB.WRITE(lob_loc, LENGTH(p_document), 1, p_document); END; / CREATE OR REPLACE PROCEDURE PRC_RD_CLOB (    p_id IN NUMBER,    p_clob OUT VARCHAR2) IS BEGIN    SELECT CLOBHOLDERDDOC INTO p_clob    FROM   TBL_CLOBHOLDERDDOC    WHERE  CLOBHOLDERDDOCID = p_id; END; /   I hope that is useful to someone!

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