date model - Page 254 - Developer IT

Getting the last member of a group on an intermediary M2M

- by rh0dium

If we look at the existing docs, what is the best way to get the last member added? This is similar to this but what I want to do is to be able to do this. group = Group.objects.get(id=1) group.get_last_member_added() #This is by ('-date_added') <Person: FOO> I think the best way is through a manager but how do you do this on an intermediary model? class Person(models.Model): name = models.CharField(max_length=128) def __unicode__(self): return self.name class Group(models.Model): name = models.CharField(max_length=128) members = models.ManyToManyField(Person, through='Membership') def __unicode__(self): return self.name class Membership(models.Model): person = models.ForeignKey(Person) group = models.ForeignKey(Group) date_joined = models.DateField() invite_reason = models.CharField(max_length=64)

Read the article

how to display one input text box..

- by kumar

hello, <input type="text" id="Date-<%=Model.ID%>" /><%=Html.EditorFor(model => model.Date)%> if I use this I am getting two input boxes on front end? Can any body help me out.. how to get only one textbox,.. thanks

Read the article

Row for each hour even if there is no record

- by peku33

I've got a trouble with creating mysql Query. My PHP script executes this query on each run: INSERT INTO Executes SET UserIp='%s' (%s is user IP) Executes table is: ExecuteId UNSIGNED BIGINT AI PRIMARY Date TIMESTAMP DEFAULT CURRENT_TIMESTAMP INDEX UserIp CHAR(24) ... | Some Columns I want to retrive number of Executes in each hour. The most obvious solution would be: SELECT COUNT(*) as ExecutesNum, DATE(Date) as D, HOUR(Date) as H GROUP BY D, H And it works, BUT it does not create rows for hours where there were no executes. What should I modify to get result like: 1 | 2012-09-01 | 14 **0 | 2012-09-01 | 15** 11 | 2012-09-01 | 16 1 | 2012-09-01 | 17

Read the article

How to insert data only if data doesn't already exist in MYSQL?

- by Lost_in_code

This is what I'm doing right now: Execute a query and check if the date to be inserted already exists in a table. If date doesn't exist: Another query will insert the date into the table. How can these two query be combined?

Read the article

django: how to use many-to-many relationships in values()?

- by john

i need to group results by a field that requires a few joins from the original model: // response_filter_args is created dynamically responses = Response.objects.filter(**response_filter_args) \ .values('customer__tags__tag') \ # django doesn't like this .annotate(average_score=Avg('rating__score')) Response - customer - tags (many-to-many field pointing to Tag) - tag (the tag as a string) Models are: class Response(models.Model): customer = models.ForeignKey(Customer) ... class Customer(models.Model): tags = models.ManyToManyField(Tag) ... class Tag(models.Model): tag = models.CharField(max_length=255) ... i'm trying to calculate average ratings. to make it work i need to tell django to group by 'tag', but it refuses to. it gives an error: Invalid field name: 'customer__tags__tag' anyone know how i can get it to group by tag? i've tried all the combinations of underscores in customer_tags_tag that i can think of, but nothing works.

Read the article

numeric choice field:How to let the user set a value by incrementing/decrementing the displayed valu

- by con_9

Hi,I have a range say,1-100 and i want the user to select a value from this range.Ofcourse showing this with a spinner will be awful.I want to use the functionality of date widget,where we can pick a date by pressing a +/- sign,the longer the press ,higher the iteration speed. I found numberpicker.java that has the code the date widget uses to get this functionality, but do i have to paste that entire code to achieve this functionality!

Read the article

Configure UIDatePicker with current locations time

- by Telkitty

I am using UIDatePicker in my current app, here is how I set a UILabel with the date time string obtained from the UIDatePicker. -(IBAction)AddTimeEnd:(id)sender { NSDate * date = [m_DateTimePicker date]; m_DateTimeLabel.text = [date description]; } Somehow the time I have entered (EST) kept on getting converted to US time in the UILabel. Does anyone know how to fix it? I would like the time entered in UIDatePicker to be consistent with the text in the label (probably the simplest way is set the locale for the UIDatePicker to be the local timezone)?

Read the article

Question About Classic MVC

- by kernix

Hello, In classic MVC the model notifies the view about changes made on it. In C# this means I have to subclass the View I'm interested in and in the subclassed class register to the model's event. For example, if I were to implement MVC using C# and Winforms, I had to subclass TextBox class and then register inside the MyTextBox's constructor for the model events. Am I correct? How was this issued in Smalltalk? Does one also need to subclass every View in order to register the model's events, or is there some way to dynamically add events to the views on the fly? Thanks

Read the article

PHP DateTime accept multiple formats?

- by John Smith

I'm trying to construct a DateTime object with multiple accepted formats. According to the DateTime::createFromFormat docs, the first parameter (format) must be a string. I was wondering if there was a way to createFromFormats. In my case, I want the year for my format to be optional: DateTime::createFromFormat('Y-m-d', $date); DateTime::createFromFormat('m-d', $date); so that a user can input just 'm-d' and the year would be assumed 2013. If I wanted multiple accepted formats, would I have to call createFromFormat each time? Shortest thing for my scenario is: DateTime::createFromFormat('m-d', $date) ?: DateTime::createFromFormat('Y-m-d', $date);

Read the article

DropDownList not working 100% in ASP.Net MVC

- by Program.X

I am quite confused with how to effectively use the Html.DropDownList helper for ASP.NET MVC. Background: I have a 5-page form, which saves data to the form each time "Next" is clicked. Users may navigate back and forth between sections, so previous sections will already be pre-populated with previously-entered data. This works for TextBoxes. But not DropDownLists. I have tried a load of different methods, including: http://stackoverflow.com/questions/867117/how-to-add-static-list-of-items-in-mvc-html-dropdownlist/867218#867218 http://stackoverflow.com/questions/2080802/setting-selected-item-to-dropdownlist-in-mvc-application I have a ViewModel such taht I have got my lists and my Model (a LINQ-to-SQL generated class) as properties. eg: public class ConsultantRegistrationFormViewModel { public IConsultantRegistration ConsultantRegistration { get; private set; } public SelectList Titles { get; private set; } public SelectList Countries { get; private set; } public SelectList Currencies { get; private set; } public int CurrentSection { get; private set; } private ConsultantRegistrationFormViewModel(IConsultantRegistration consultantRegistration) { ConsultantRegistration = consultantRegistration; CurrentSection = 1; Titles = new SelectList(new string[] { "Mr", "Mrs", "Miss", "Ms", "Dr", "Sir" }); Countries = new SelectList(countries.Select(q => q.Name)); Currencies = new SelectList(currencies,"CurrencyCode","FriendlyForm"); } } My Controller's Edit Action on GET looks like: public class ConsultantRegistrationController : Controller { public IConsultantRegistrationRepository ConsultantRegistrationRepository { get; private set; } public ICountryRepository CountryRepository { get; private set; } public IEnumerable<ICountry> Countries { get; private set; } public ConsultantRegistrationController() { ConsultantRegistrationRepository = RepositoryFactory.CreateConsultantRegistrationRepository(); CountryRepository = RepositoryFactory.CreateCountryRepository(); Countries = CountryRepository.GetCountries().ToArray(); } public ActionResult Edit(Guid id, int sectionIndex) { IConsultantRegistration consultantRegistration = ConsultantRegistrationRepository.GetConsultantRegistration(id); SelectList bankBranchCountriesSelectList = new SelectList(Countries, "BankBranchCountry", "CountryName", consultantRegistration.BankBranchCountry); ViewData["bankBranchCountrySelectList"] = bankBranchCountriesSelectList; return View(new ConsultantRegistrationFormViewModel(consultantRegistration,sectionIndex, Countries,Currencies)); } } With my View doing: <%: Html.DropDownList("ConsultantRegistration.BankBranchCountry",ViewData["bankBranchCountrySelectList"] as SelectList) %> This gives me the error: DataBinding: 'IWW.ArrowPay.ConsultantRegistration.Data.Country' does not contain a property with the name 'BankBranchCountry'. Which it does, have a look at the schema of this property: public interface IConsultantRegistration { Guid ID { get; set; } [DisplayName("Branch Country")] string BankBranchCountry { get; set; } } (My LINQ-to-SQL type ConsultantRegistration implemented IConsultantRegistration) It seems that it is trying to bind to the wrong type, though? If I use this in my view (and use my Controller's Countries property): <%: Html.DropDownList("ConsultantRegistration.BankBranchCountry ",Model.Countries,"(select a Country)") %> I get the saved value fine, but my model doesn't update on POST. And if I use this in my view: <%: Html.DropDownListFor(model=>model.ConsultantRegistration.BankBranchCountry ",Model.Countries,"(select a Country)") %> I get the list, and it POSTs the selected value back, but does not pre-select the currently selected item in my model on the view. So I have a bit of the solution all over the place, but not all in one place. Hope you can help fill in my ignorance.

Read the article

converting timestamp to nanoseconds

- by kuki

I have a certain value of date and time say 28-3-2012(date) - 10:36:45(time) . I wish to convert this whole timestamp to nanoseconds with the precision of nanoseconds. As in the user would input the time and date as shown but internally i have to be accurate upto nanoseconds and convert the whole thing to nanoseconds to form a unique key assigned to a specific object created at that particular time. Could some one please help me with the same..

Read the article

ASP.NET MVC 3 - New Features

- by imran_ku07

Introduction: ASP.NET MVC 3 just released by ASP.NET MVC team which includes some new features, some changes, some improvements and bug fixes. In this article, I will show you the new features of ASP.NET MVC 3. This will help you to get started using the new features of ASP.NET MVC 3. Full details of this announcement is available at Announcing release of ASP.NET MVC 3, IIS Express, SQL CE 4, Web Farm Framework, Orchard, WebMatrix. Description: New Razor View Engine: Razor view engine is one of the most coolest new feature in ASP.NET MVC 3. Razor is speeding things up just a little bit more. It is much smaller and lighter in size. Also it is very easy to learn. You can say ' write less, do more '. You can get start and learn more about Razor at Introducing “Razor” – a new view engine for ASP.NET. Granular Request Validation: Another biggest new feature in ASP.NET MVC 3 is Granular Request Validation. Default request validator will throw an exception when he see < followed by an exclamation(like <!) or < followed by the letters a through z(like <s) or & followed by a pound sign(like &#123) as a part of querystring, posted form, headers and cookie collection. In previous versions of ASP.NET MVC, you can control request validation using ValidateInputAttriubte. In ASP.NET MVC 3 you can control request validation at Model level by annotating your model properties with a new attribute called AllowHtmlAttribute. For details see Granular Request Validation in ASP.NET MVC 3. Sessionless Controller Support: Sessionless Controller is another great new feature in ASP.NET MVC 3. With Sessionless Controller you can easily control your session behavior for controllers. For example, you can make your HomeController's Session as Disabled or ReadOnly, allowing concurrent request execution for single user. For details see Concurrent Requests In ASP.NET MVC and HowTo: Sessionless Controller in MVC3 – what & and why?. Unobtrusive Ajax and Unobtrusive Client Side Validation is Supported: Another cool new feature in ASP.NET MVC 3 is support for Unobtrusive Ajax and Unobtrusive Client Side Validation. This feature allows separation of responsibilities within your web application by separating your html with your script. For details see Unobtrusive Ajax in ASP.NET MVC 3 and Unobtrusive Client Validation in ASP.NET MVC 3. Dependency Resolver: Dependency Resolver is another great feature of ASP.NET MVC 3. It allows you to register a dependency resolver that will be used by the framework. With this approach your application will not become tightly coupled and the dependency will be injected at run time. For details see ASP.NET MVC 3 Service Location. New Helper Methods: ASP.NET MVC 3 includes some helper methods of ASP.NET Web Pages technology that are used for common functionality. These helper methods includes: Chart, Crypto, WebGrid, WebImage and WebMail. For details of these helper methods, please see ASP.NET MVC 3 Release Notes. For using other helper methods of ASP.NET Web Pages see Using ASP.NET Web Pages Helpers in ASP.NET MVC. Child Action Output Caching: ASP.NET MVC 3 also includes another feature called Child Action Output Caching. This allows you to cache only a portion of the response when you are using Html.RenderAction or Html.Action. This cache can be varied by action name, action method signature and action method parameter values. For details see this. RemoteAttribute: ASP.NET MVC 3 allows you to validate a form field by making a remote server call through Ajax. This makes it very easy to perform remote validation at client side and quickly give the feedback to the user. For details see How to: Implement Remote Validation in ASP.NET MVC. CompareAttribute: ASP.NET MVC 3 includes a new validation attribute called CompareAttribute. CompareAttribute allows you to compare the values of two different properties of a model. For details see CompareAttribute in ASP.NET MVC 3. Miscellaneous New Features: ASP.NET MVC 2 includes FormValueProvider, QueryStringValueProvider, RouteDataValueProvider and HttpFileCollectionValueProvider. ASP.NET MVC 3 adds two additional value providers, ChildActionValueProvider and JsonValueProvider(JsonValueProvider is not physically exist). ChildActionValueProvider is used when you issue a child request using Html.Action and/or Html.RenderAction methods, so that your explicit parameter values in Html.Action and/or Html.RenderAction will always take precedence over other value providers. JsonValueProvider is used to model bind JSON data. For details see Sending JSON to an ASP.NET MVC Action Method Argument. In ASP.NET MVC 3, a new property named FileExtensions added to the VirtualPathProviderViewEngine class. This property is used when looking up a view by path (and not by name), so that only views with a file extension contained in the list specified by this new property is considered. For details see VirtualPathProviderViewEngine.FileExtensions Property . ASP.NET MVC 3 installation package also includes the NuGet Package Manager which will be automatically installed when you install ASP.NET MVC 3. NuGet makes it easy to install and update open source libraries and tools in Visual Studio. See this for details. In ASP.NET MVC 2, client side validation will not trigger for overridden model properties. For example, if have you a Model that contains some overridden properties then client side validation will not trigger for overridden properties in ASP.NET MVC 2 but client side validation will work for overridden properties in ASP.NET MVC 3. Client side validation is not supported for StringLengthAttribute.MinimumLength property in ASP.NET MVC 2. In ASP.NET MVC 3 client side validation will work for StringLengthAttribute.MinimumLength property. ASP.NET MVC 3 includes new action results like HttpUnauthorizedResult, HttpNotFoundResult and HttpStatusCodeResult. ASP.NET MVC 3 includes some new overloads of LabelFor and LabelForModel methods. For details see LabelExtensions.LabelForModel and LabelExtensions.LabelFor. In ASP.NET MVC 3, IControllerFactory includes a new method GetControllerSessionBehavior. This method is used to get controller's session behavior. For details see IControllerFactory.GetControllerSessionBehavior Method. In ASP.NET MVC 3, Controller class includes a new property ViewBag which is of type dynamic. This property allows you to access ViewData Dictionary using C # 4.0 dynamic features. For details see ControllerBase.ViewBag Property. ModelMetadata includes a property AdditionalValues which is of type Dictionary. In ASP.NET MVC 3 you can populate this property using AdditionalMetadataAttribute. For details see AdditionalMetadataAttribute Class. In ASP.NET MVC 3 you can also use MvcScaffolding to scaffold your Views and Controller. For details see Scaffold your ASP.NET MVC 3 project with the MvcScaffolding package. If you want to convert your application from ASP.NET MVC 2 to ASP.NET MVC 3 then there is an excellent tool that automatically converts ASP.NET MVC 2 application to ASP.NET MVC 3 application. For details see MVC 3 Project Upgrade Tool. In ASP.NET MVC 2 DisplayAttribute is not supported but in ASP.NET MVC 3 DisplayAttribute will work properly. ASP.NET MVC 3 also support model level validation via the new IValidatableObject interface. ASP.NET MVC 3 includes a new helper method Html.Raw. This helper method allows you to display unencoded HTML. Summary: In this article I showed you the new features of ASP.NET MVC 3. This will help you a lot when you start using ASP MVC 3. I also provide you the links where you can find further details. Hopefully you will enjoy this article too.

Read the article

ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager

- by rajbk

This post walks you through creating a UI for paging, sorting and filtering a list of data items. It makes use of the excellent MVCContrib Grid and Pager Html UI helpers. A sample project is attached at the bottom. Our UI will eventually look like this. The application will make use of the Northwind database. The top portion of the page has a filter area region. The filter region is enclosed in a form tag. The select lists are wired up with jQuery to auto post back the form. The page has a pager region at the top and bottom of the product list. The product list has a link to display more details about a given product. The column headings are clickable for sorting and an icon shows the sort direction. Strongly Typed View Models The views are written to expect strongly typed objects. We suffix these strongly typed objects with ViewModel since they are designed specifically for passing data down to the view. The following listing shows the ProductViewModel. This class will be used to hold information about a Product. We use attributes to specify if the property should be hidden and what its heading in the table should be. This metadata will be used by the MvcContrib Grid to render the table. Some of the properties are hidden from the UI ([ScaffoldColumn(false)) but are needed because we will be using those for filtering when writing our LINQ query. public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) { var productList = productRepository.GetProductsProjected(); // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; } // Filter on SupplierID if (supplierID.HasValue) { productList = productList.Where(a => a.SupplierID == supplierID); } // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); } // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); } // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill(); // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10); var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions }; return View(productListContainer); } The following diagram shows the rest of the key ViewModels in our design. We have a container class called ProductListContainerViewModel which has nested classes. The ProductPagedList is of type IPagination<ProductViewModel>. The MvcContrib expects the IPagination<T> interface to determine the page number and page size of the collection we are working with. You convert any IEnumerable<T> into an IPagination<T> by calling the AsPagination extension method in the MvcContrib library. It also creates a paged set of type ProductViewModel. The ProductFilterViewModel class will hold information about the different select lists and the ProductName being searched on. It will also hold state of any previously selected item in the lists and the previous search criteria (you will recall that this type of state information was stored in Viewstate when working with WebForms). With MVC there is no state storage and so all state has to be fetched and passed back to the view. The GridSortOptions is a type defined in the MvcContrib library and is used by the Grid to determine the current column being sorted on and the current sort direction. The following shows the view and partial views used to render our UI. The Index view expects a type ProductListContainerViewModel which we described earlier. <%Html.RenderPartial("SearchFilters", Model.ProductFilterViewModel); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> <% Html.RenderPartial("SearchResults", Model); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> The View contains a partial view “SearchFilters” and passes it the ProductViewFilterContainer. The SearchFilter uses this Model to render all the search lists and textbox. The partial view “Pager” uses the ProductPageList which implements the interface IPagination. The “Pager” view contains the MvcContrib Pager helper used to render the paging information. This view is repeated twice since we want the pager UI to be available at the top and bottom of the product list. The Pager partial view is located in the Shared directory so that it can be reused across Views. The partial view “SearchResults” uses the ProductListContainer model. This partial view contains the MvcContrib Grid which needs both the ProdctPagedList and GridSortOptions to render itself. The Controller Action An example of a request like this: /Products?productName=test&supplierId=29&categoryId=4. The application receives this GET request and maps it to the Index method of the ProductController. Within the action we create an IQueryable<ProductViewModel> by calling the GetProductsProjected() method. /// <summary> /// This method takes in a filter list, paging/sort options and applies /// them to an IQueryable of type ProductViewModel /// </summary> /// <returns> /// The return object is a container that holds the sorted/paged list, /// state for the fiters and state about the current sorted column /// </returns> public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) { var productList = productRepository.GetProductsProjected(); // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; } // Filter on SupplierID if (supplierID.HasValue) { productList.Where(a => a.SupplierID == supplierID); } // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); } // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); } // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill(); // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10); var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions }; return View(productListContainer); } The supplier, category and productname filters are applied to this IQueryable if any are present in the request. The ProductPagedList class is created by applying a sort order and calling the AsPagination method. Finally the ProductListContainerViewModel class is created and returned to the view. You have seen how to use strongly typed views with the MvcContrib Grid and Pager to render a clean lightweight UI with strongly typed views. You also saw how to use partial views to get data from the strongly typed model passed to it from the parent view. The code also shows you how to use jQuery to auto post back. The sample is attached below. Don’t forget to change your connection string to point to the server containing the Northwind database. NorthwindSales_MvcContrib.zip My name is Kobayashi. I work for Keyser Soze.

Read the article

Building services with .Net Part 1

- by Allan Rwakatungu

On the 26th of May 2010 , I made a presentation to the .NET user group meeting (thanks to Malisa Ncube for organizing this event every month … ). If you missed my presentation , we talked about why we should all be building services … better still using the .NET framework. This blog post is an introduction to services , why you would want to build services and how you can build services using the .NET framework. What is a service? OASIS defines service as "a mechanism to enable access to one or more capabilities, where the access is provided using a prescribed interface and is exercised consistent with constraints and policies as specified by the service description." [1]. If the above definition sounds to academic , you can also define a service as loosely coupled units of functionality that have no calls to each other embedded in the. Instead of services embedding calls to each other in their service code they use defined protocols that describe how services pass and parse messages. This is a good way to think about services if you’re from an objected oriented background. While in object oriented programming functions make calls to each other, in service oriented programming, functions pass messages between each other. Why would you want to use services? 1. If your enterprise architecture looks like this Services are the building blocks for SOA . With SOA you can move away from the sphaggetti infrastructure that is common in most enterprises. The complexity or lack of visibility of the integration points in your enterprises makes it difficult and costly to implement new initiatives and changes into the business - and even impossible in some cases - as it is not possible to identify the impact a change in one system might have to other systems. With services you can move to an architecture like this Your building blocks from Spaghetti infrastructure to something that is more well-defined and manageable to achieve cost efficiency and not least business agility - enabling you to react to changes in the market with speed and achieve operational efficiency and control are services. 2. If you want to become the Gates or Zuckerburger. Have you heard about Web 2.0 ? Mashups? Software as a service (SAAS) ? Cloud computing ? They all offer you the opportunity to have scalable but low cost business models and they built using services. Some of my favorite companies that leverage services for their business models include https://www.salesforce.com/ (cloud CRM) http://www. twitter.com (more people use twitter clients built by 3rd parties than their official clients) http://www.kayak.com/ (compares data from other travel sites to give information to users in one location) Services with the .NET framework If you are a .NET developer and you want to develop services, Windows Communication Framework (WCF) is the tool for you. WCF is Microsoft’s unified programming model (service model) for building service oriented applications. ( Before .NET 3.0 you had several models for programming services in .NET including .NET remoting, Web services (ASMX), COM +, Microsoft Messaging queuing (MSMQ) etc, after .NET 3.0 the programming model was unified into one i.e. WCF ). Windows Communication Framework (WCF) provides you 1. An Software Development Kit (SDK) for creating SOA applications 2. A runtime for running services on the Windows platform Why should you use Windows Communication Foundation if you’re programming services? 1. It supports interoperable and open standards e.g. WS* protocols for programming SOAP services 2. It has a unified programming model. Whether you use TCP or Http or Pipes or transmitting using Messaging Queues, programmers need to learn just one way to program. Previously you had .NET remoting, MSMQ, Web services, COM+ and they were all done differently 3. Productive programming model You don’t have to worry about all the plumbing involved to write services. You have a rich declarative programming model to add stuff like logging, transactions, and reliable messages in-built in the Windows Communication Framework. Understanding services in WCF The basic principles of WCF are as easy as ABC A – Address This is where the service is located B- Binding This describes how you communicate with the service e.g. Use TCP, HTTP or both. How to exchange security information with the service etc. C – Contract This defines what the service can do. E.g. Pay water bill, Make a phone call A - Addresses In WCF, an address is a combination of transport, server name, port and path Example addresses may include http://localhost:8001 net.tcp://localhost:8002/MyService net.pipe://localhost/MyPipe net.msmq://localhost/private/MyService net.msmq://localhost/MyService B- Binding There are numerous ways to communicate with services , different ways that a message can be formatted/sent/secured, that allows you to tailor your service for the compatibility/performance you require for your solution. Transport You can use HTTP TCP MSMQ , Named pipes, Your own custom transport etc Message You can send a plain text binary, Message Transmission Optimization Mechanism (MTOM) message Communication security No security Transport security Message security Authenticating and authorizing callers etc Behaviour You service can support Transactions Be reliable Use queues Support ajax etc C - Contract You define what your service can do using Service contracts :- Define operations that your service can do, communications and behaviours Data contracts :- Define the messages that are passed from and into your service and how they are formatted Fault contracts :- Defines errors types in your service As an example, suppose your service service shows money. You define your service contract using a interface [ServiceContract] public interface IShowMeTheMoney { [OperationContract] Money Show(); } You define the data contract by annotating a class it with the Data Contract attribute and fields you want to pass in the message as Data Members. (Note:- In the latest versions of WCF you dont have to use attributes if you passing all the objects properties in the message) [DataContract] public Money { [DataMember] public string Currency { get; set; } [DataMember] public Decimal Amount { get; set; } public string Comment { get; set; } } Features of Windows Communication Foundation Windows Communication Foundation is not only simple but feature rich , offering you several options to tweak your service to fit your business requirements. Some of the features of WCF include 1. Workflow services You can combine WCF with Windows WorkFlow Foundation (WWF) to write workflow type services 2. Control how your data (messages) are transferred and serialized e.g. you can serialize your business objects as XML or binary 3. control over session management , instance creation and concurrency management without writing code if you like 4. Queues and reliable sessions. You can store messages from the sending client and later forward them to the receiving application. You can also guarantee that messages will arrive at their destincation. 5.Transactions: You can have different services participate in a transaction operations that can be rolled back if needed 6. Security. WCF has rich features for authorization and authentication as well as keep audit trails 7. Web programming model. WCF allows developers to expose services as non SOAP endpoints 8. Inbuilt features that you can use to write JSON and services that support AJAX applications And lots more In my next blog I will show you how you can use WCF features to write a real world business service. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 ]] /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

Read the article

Following the Thread in OSB

- by Antony Reynolds

Threading in OSB The Scenario I recently led an OSB POC where we needed to get high throughput from an OSB pipeline that had the following logic: 1. Receive Request 2. Send Request to External System 3. If Response has a particular value 3.1 Modify Request 3.2 Resend Request to External System 4. Send Response back to Requestor All looks very straightforward and no nasty wrinkles along the way. The flow was implemented in OSB as follows (see diagram for more details): Proxy Service to Receive Request and Send Response Request Pipeline Copies Original Request for use in step 3 Route Node Sends Request to External System exposed as a Business Service Response Pipeline Checks Response to Check If Request Needs to Be Resubmitted Modify Request Callout to External System (same Business Service as Route Node) The Proxy and the Business Service were each assigned their own Work Manager, effectively giving each of them their own thread pool. The Surprise Imagine our surprise when, on stressing the system we saw it lock up, with large numbers of blocked threads. The reason for the lock up is due to some subtleties in the OSB thread model which is the topic of this post. Basic Thread Model OSB goes to great lengths to avoid holding on to threads. Lets start by looking at how how OSB deals with a simple request/response routing to a business service in a route node. Most Business Services are implemented by OSB in two parts. The first part uses the request thread to send the request to the target. In the diagram this is represented by the thread T1. After sending the request to the target (the Business Service in our diagram) the request thread is released back to whatever pool it came from. A multiplexor (muxer) is used to wait for the response. When the response is received the muxer hands off the response to a new thread that is used to execute the response pipeline, this is represented in the diagram by T2. OSB allows you to assign different Work Managers and hence different thread pools to each Proxy Service and Business Service. In out example we have the “Proxy Service Work Manager” assigned to the Proxy Service and the “Business Service Work Manager” assigned to the Business Service. Note that the Business Service Work Manager is only used to assign the thread to process the response, it is never used to process the request. This architecture means that while waiting for a response from a business service there are no threads in use, which makes for better scalability in terms of thread usage. First Wrinkle Note that if the Proxy and the Business Service both use the same Work Manager then there is potential for starvation. For example: Request Pipeline makes a blocking callout, say to perform a database read. Business Service response tries to allocate a thread from thread pool but all threads are blocked in the database read. New requests arrive and contend with responses arriving for the available threads. Similar problems can occur if the response pipeline blocks for some reason, maybe a database update for example. Solution The solution to this is to make sure that the Proxy and Business Service use different Work Managers so that they do not contend with each other for threads. Do Nothing Route Thread Model So what happens if there is no route node? In this case OSB just echoes the Request message as a Response message, but what happens to the threads? OSB still uses a separate thread for the response, but in this case the Work Manager used is the Default Work Manager. So this is really a special case of the Basic Thread Model discussed above, except that the response pipeline will always execute on the Default Work Manager. Proxy Chaining Thread Model So what happens when the route node is actually calling a Proxy Service rather than a Business Service, does the second Proxy Service use its own Thread or does it re-use the thread of the original Request Pipeline? Well as you can see from the diagram when a route node calls another proxy service then the original Work Manager is used for both request pipelines. Similarly the response pipeline uses the Work Manager associated with the ultimate Business Service invoked via a Route Node. This actually fits in with the earlier description I gave about Business Services and by extension Route Nodes they “… uses the request thread to send the request to the target”. Call Out Threading Model So what happens when you make a Service Callout to a Business Service from within a pipeline. The documentation says that “The pipeline processor will block the thread until the response arrives asynchronously” when using a Service Callout. What this means is that the target Business Service is called using the pipeline thread but the response is also handled by the pipeline thread. This implies that the pipeline thread blocks waiting for a response. It is the handling of this response that behaves in an unexpected way. When a Business Service is called via a Service Callout, the calling thread is suspended after sending the request, but unlike the Route Node case the thread is not released, it waits for the response. The muxer uses the Business Service Work Manager to allocate a thread to process the response, but in this case processing the response means getting the response and notifying the blocked pipeline thread that the response is available. The original pipeline thread can then continue to process the response. Second Wrinkle This leads to an unfortunate wrinkle. If the Business Service is using the same Work Manager as the Pipeline then it is possible for starvation or a deadlock to occur. The scenario is as follows: Pipeline makes a Callout and the thread is suspended but still allocated Multiple Pipeline instances using the same Work Manager are in this state (common for a system under load) Response comes back but all Work Manager threads are allocated to blocked pipelines. Response cannot be processed and so pipeline threads never unblock – deadlock! Solution The solution to this is to make sure that any Business Services used by a Callout in a pipeline use a different Work Manager to the pipeline itself. The Solution to My Problem Looking back at my original workflow we see that the same Business Service is called twice, once in a Routing Node and once in a Response Pipeline Callout. This was what was causing my problem because the response pipeline was using the Business Service Work Manager, but the Service Callout wanted to use the same Work Manager to handle the responses and so eventually my Response Pipeline hogged all the available threads so no responses could be processed. The solution was to create a second Business Service pointing to the same location as the original Business Service, the only difference was to assign a different Work Manager to this Business Service. This ensured that when the Service Callout completed there were always threads available to process the response because the response processing from the Service Callout had its own dedicated Work Manager. Summary Request Pipeline Executes on Proxy Work Manager (WM) Thread so limited by setting of that WM. If no WM specified then uses WLS default WM. Route Node Request sent using Proxy WM Thread Proxy WM Thread is released before getting response Muxer is used to handle response Muxer hands off response to Business Service (BS) WM Response Pipeline Executes on Routed Business Service WM Thread so limited by setting of that WM. If no WM specified then uses WLS default WM. No Route Node (Echo functionality) Proxy WM thread released New thread from the default WM used for response pipeline Service Callout Request sent using proxy pipeline thread Proxy thread is suspended (not released) until the response comes back Notification of response handled by BS WM thread so limited by setting of that WM. If no WM specified then uses WLS default WM. Note this is a very short lived use of the thread After notification by callout BS WM thread that thread is released and execution continues on the original pipeline thread. Route/Callout to Proxy Service Request Pipeline of callee executes on requestor thread Response Pipeline of caller executes on response thread of requested proxy Throttling Request message may be queued if limit reached. Requesting thread is released (route node) or suspended (callout) So what this means is that you may get deadlocks caused by thread starvation if you use the same thread pool for the business service in a route node and the business service in a callout from the response pipeline because the callout will need a notification thread from the same thread pool as the response pipeline. This was the problem we were having. You get a similar problem if you use the same work manager for the proxy request pipeline and a business service callout from that request pipeline. It also means you may want to have different work managers for the proxy and business service in the route node. Basically you need to think carefully about how threading impacts your proxy services. References Thanks to Jay Kasi, Gerald Nunn and Deb Ayers for helping to explain this to me. Any errors are my own and not theirs. Also thanks to my colleagues Milind Pandit and Prasad Bopardikar who travelled this road with me. OSB Thread Model Great Blog Post on Thread Usage in OSB

Read the article

Juju Openstack bundle: Can't launch an instance

- by user281985

Deployed bundle:~makyo/openstack/2/openstack, on top of 7 physical boxes and 3 virtual ones. After changing vip_iface strings to point to right devices, e.g., br0 instead of eth0, and defining "/mnt/loopback|30G", in Cinder's block-device string, am able to navigate through openstack dashboard, error free. Following http://docs.openstack.org/grizzly/openstack-compute/install/apt/content/running-an-instance.html instructions, attempted to launch cirros 0.3.1 image; however, novalist shows the instance in error state. ubuntu@node7:~$ nova --debug boot --flavor 1 --image 28bed1bc-bc1c-4533-beee-8e0428ad40dd --key_name key2 --security_group default cirros REQ: curl -i http://keyStone.IP:5000/v2.0/tokens -X POST -H "Content-Type: application/json" -H "Accept: application/json" -H "User-Agent: python-novaclient" -d '{"auth": {"tenantName": "admin", "passwordCredentials": {"username": "admin", "password": "openstack"}}}' INFO (connectionpool:191) Starting new HTTP connection (1): keyStone.IP DEBUG (connectionpool:283) "POST /v2.0/tokens HTTP/1.1" 200 None RESP: [200] {'date': 'Tue, 10 Jun 2014 00:01:02 GMT', 'transfer-encoding': 'chunked', 'vary': 'X-Auth-Token', 'content-type': 'application/json'} RESP BODY: {"access": {"token": {"expires": "2014-06-11T00:01:02Z", "id": "3eefa1837d984426a633fe09259a1534", "tenant": {"description": "Created by Juju", "enabled": true, "id": "08cff06d13b74492b780d9ceed699239", "name": "admin"}}, "serviceCatalog": [{"endpoints": [{"adminURL": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239", "region": "RegionOne", "internalURL": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239", "publicURL": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239"}], "endpoints_links": [], "type": "compute", "name": "nova"}, {"endpoints": [{"adminURL": "http://nova.cloud.controller:9696", "region": "RegionOne", "internalURL": "http://nova.cloud.controller:9696", "publicURL": "http://nova.cloud.controller:9696"}], "endpoints_links": [], "type": "network", "name": "quantum"}, {"endpoints": [{"adminURL": "http://nova.cloud.controller:3333", "region": "RegionOne", "internalURL": "http://nova.cloud.controller:3333", "publicURL": "http://nova.cloud.controller:3333"}], "endpoints_links": [], "type": "s3", "name": "s3"}, {"endpoints": [{"adminURL": "http://i.p.s.36:9292", "region": "RegionOne", "internalURL": "http://i.p.s.36:9292", "publicURL": "http://i.p.s.36:9292"}], "endpoints_links": [], "type": "image", "name": "glance"}, {"endpoints": [{"adminURL": "http://i.p.s.39:8776/v1/08cff06d13b74492b780d9ceed699239", "region": "RegionOne", "internalURL": "http://i.p.s.39:8776/v1/08cff06d13b74492b780d9ceed699239", "publicURL": "http://i.p.s.39:8776/v1/08cff06d13b74492b780d9ceed699239"}], "endpoints_links": [], "type": "volume", "name": "cinder"}, {"endpoints": [{"adminURL": "http://nova.cloud.controller:8773/services/Cloud", "region": "RegionOne", "internalURL": "http://nova.cloud.controller:8773/services/Cloud", "publicURL": "http://nova.cloud.controller:8773/services/Cloud"}], "endpoints_links": [], "type": "ec2", "name": "ec2"}, {"endpoints": [{"adminURL": "http://keyStone.IP:35357/v2.0", "region": "RegionOne", "internalURL": "http://keyStone.IP:5000/v2.0", "publicURL": "http://i.p.s.44:5000/v2.0"}], "endpoints_links": [], "type": "identity", "name": "keystone"}], "user": {"username": "admin", "roles_links": [], "id": "b3730a52a32e40f0a9500440d1ef1c7d", "roles": [{"id": "e020001eb9a049f4a16540238ab158aa", "name": "Admin"}, {"id": "b84fbff4d5554d53bbbffdaad66b56cb", "name": "KeystoneServiceAdmin"}, {"id": "129c8b49d42b4f0796109aaef2069aa9", "name": "KeystoneAdmin"}], "name": "admin"}}} REQ: curl -i http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd -X GET -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Accept: application/json" -H "X-Auth-Token: 3eefa1837d984426a633fe09259a1534" INFO (connectionpool:191) Starting new HTTP connection (1): nova.cloud.controller DEBUG (connectionpool:283) "GET /v1.1/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd HTTP/1.1" 200 719 RESP: [200] {'date': 'Tue, 10 Jun 2014 00:01:03 GMT', 'x-compute-request-id': 'req-7f3459f8-d3d5-47f1-97a3-8407a4419a69', 'content-type': 'application/json', 'content-length': '719'} RESP BODY: {"image": {"status": "ACTIVE", "updated": "2014-06-09T22:17:54Z", "links": [{"href": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "rel": "self"}, {"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "rel": "bookmark"}, {"href": "http://External.Public.Port:9292/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "type": "application/vnd.openstack.image", "rel": "alternate"}], "id": "28bed1bc-bc1c-4533-beee-8e0428ad40dd", "OS-EXT-IMG-SIZE:size": 13147648, "name": "Cirros 0.3.1", "created": "2014-06-09T22:17:54Z", "minDisk": 0, "progress": 100, "minRam": 0, "metadata": {}}} REQ: curl -i http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/flavors/1 -X GET -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Accept: application/json" -H "X-Auth-Token: 3eefa1837d984426a633fe09259a1534" INFO (connectionpool:191) Starting new HTTP connection (1): nova.cloud.controller DEBUG (connectionpool:283) "GET /v1.1/08cff06d13b74492b780d9ceed699239/flavors/1 HTTP/1.1" 200 418 RESP: [200] {'date': 'Tue, 10 Jun 2014 00:01:04 GMT', 'x-compute-request-id': 'req-2c153110-6969-4f3a-b51c-8f1a6ce75bee', 'content-type': 'application/json', 'content-length': '418'} RESP BODY: {"flavor": {"name": "m1.tiny", "links": [{"href": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/flavors/1", "rel": "self"}, {"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/flavors/1", "rel": "bookmark"}], "ram": 512, "OS-FLV-DISABLED:disabled": false, "vcpus": 1, "swap": "", "os-flavor-access:is_public": true, "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 0, "disk": 0, "id": "1"}} REQ: curl -i http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/servers -X POST -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: 3eefa1837d984426a633fe09259a1534" -d '{"server": {"name": "cirros", "imageRef": "28bed1bc-bc1c-4533-beee-8e0428ad40dd", "key_name": "key2", "flavorRef": "1", "max_count": 1, "min_count": 1, "security_groups": [{"name": "default"}]}}' INFO (connectionpool:191) Starting new HTTP connection (1): nova.cloud.controller DEBUG (connectionpool:283) "POST /v1.1/08cff06d13b74492b780d9ceed699239/servers HTTP/1.1" 202 436 RESP: [202] {'date': 'Tue, 10 Jun 2014 00:01:05 GMT', 'x-compute-request-id': 'req-41e53086-6454-4efb-bb35-a30dc2c780be', 'content-type': 'application/json', 'location': 'http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43', 'content-length': '436'} RESP BODY: {"server": {"security_groups": [{"name": "default"}], "OS-DCF:diskConfig": "MANUAL", "id": "2eb5e3ad-3044-41c1-bbb7-10f398f83e43", "links": [{"href": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43", "rel": "self"}, {"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43", "rel": "bookmark"}], "adminPass": "oFRbvRqif2C8"}} REQ: curl -i http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43 -X GET -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Accept: application/json" -H "X-Auth-Token: 3eefa1837d984426a633fe09259a1534" INFO (connectionpool:191) Starting new HTTP connection (1): nova.cloud.controller DEBUG (connectionpool:283) "GET /v1.1/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43 HTTP/1.1" 200 1349 RESP: [200] {'date': 'Tue, 10 Jun 2014 00:01:05 GMT', 'x-compute-request-id': 'req-d91d0858-7030-469d-8e55-40e05e4d00fd', 'content-type': 'application/json', 'content-length': '1349'} RESP BODY: {"server": {"status": "BUILD", "updated": "2014-06-10T00:01:05Z", "hostId": "", "OS-EXT-SRV-ATTR:host": null, "addresses": {}, "links": [{"href": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43", "rel": "self"}, {"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/servers/2eb5e3ad-3044-41c1-bbb7-10f398f83e43", "rel": "bookmark"}], "key_name": "key2", "image": {"id": "28bed1bc-bc1c-4533-beee-8e0428ad40dd", "links": [{"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "rel": "bookmark"}]}, "OS-EXT-STS:task_state": "scheduling", "OS-EXT-STS:vm_state": "building", "OS-EXT-SRV-ATTR:instance_name": "instance-00000004", "OS-EXT-SRV-ATTR:hypervisor_hostname": null, "flavor": {"id": "1", "links": [{"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/flavors/1", "rel": "bookmark"}]}, "id": "2eb5e3ad-3044-41c1-bbb7-10f398f83e43", "security_groups": [{"name": "default"}], "OS-EXT-AZ:availability_zone": "nova", "user_id": "b3730a52a32e40f0a9500440d1ef1c7d", "name": "cirros", "created": "2014-06-10T00:01:04Z", "tenant_id": "08cff06d13b74492b780d9ceed699239", "OS-DCF:diskConfig": "MANUAL", "accessIPv4": "", "accessIPv6": "", "progress": 0, "OS-EXT-STS:power_state": 0, "config_drive": "", "metadata": {}}} REQ: curl -i http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/flavors/1 -X GET -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Accept: application/json" -H "X-Auth-Token: 3eefa1837d984426a633fe09259a1534" INFO (connectionpool:191) Starting new HTTP connection (1): nova.cloud.controller DEBUG (connectionpool:283) "GET /v1.1/08cff06d13b74492b780d9ceed699239/flavors/1 HTTP/1.1" 200 418 RESP: [200] {'date': 'Tue, 10 Jun 2014 00:01:05 GMT', 'x-compute-request-id': 'req-896c0120-1102-4408-9e09-cd628f2dd699', 'content-type': 'application/json', 'content-length': '418'} RESP BODY: {"flavor": {"name": "m1.tiny", "links": [{"href": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/flavors/1", "rel": "self"}, {"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/flavors/1", "rel": "bookmark"}], "ram": 512, "OS-FLV-DISABLED:disabled": false, "vcpus": 1, "swap": "", "os-flavor-access:is_public": true, "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 0, "disk": 0, "id": "1"}} REQ: curl -i http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd -X GET -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Accept: application/json" -H "X-Auth-Token: 3eefa1837d984426a633fe09259a1534" INFO (connectionpool:191) Starting new HTTP connection (1): nova.cloud.controller DEBUG (connectionpool:283) "GET /v1.1/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd HTTP/1.1" 200 719 RESP: [200] {'date': 'Tue, 10 Jun 2014 00:01:05 GMT', 'x-compute-request-id': 'req-454e9651-c247-4d31-8049-6b254de050ae', 'content-type': 'application/json', 'content-length': '719'} RESP BODY: {"image": {"status": "ACTIVE", "updated": "2014-06-09T22:17:54Z", "links": [{"href": "http://nova.cloud.controller:8774/v1.1/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "rel": "self"}, {"href": "http://nova.cloud.controller:8774/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "rel": "bookmark"}, {"href": "http://External.Public.Port:9292/08cff06d13b74492b780d9ceed699239/images/28bed1bc-bc1c-4533-beee-8e0428ad40dd", "type": "application/vnd.openstack.image", "rel": "alternate"}], "id": "28bed1bc-bc1c-4533-beee-8e0428ad40dd", "OS-EXT-IMG-SIZE:size": 13147648, "name": "Cirros 0.3.1", "created": "2014-06-09T22:17:54Z", "minDisk": 0, "progress": 100, "minRam": 0, "metadata": {}}} +-------------------------------------+--------------------------------------+ | Property | Value | +-------------------------------------+--------------------------------------+ | OS-EXT-STS:task_state | scheduling | | image | Cirros 0.3.1 | | OS-EXT-STS:vm_state | building | | OS-EXT-SRV-ATTR:instance_name | instance-00000004 | | flavor | m1.tiny | | id | 2eb5e3ad-3044-41c1-bbb7-10f398f83e43 | | security_groups | [{u'name': u'default'}] | | user_id | b3730a52a32e40f0a9500440d1ef1c7d | | OS-DCF:diskConfig | MANUAL | | accessIPv4 | | | accessIPv6 | | | progress | 0 | | OS-EXT-STS:power_state | 0 | | OS-EXT-AZ:availability_zone | nova | | config_drive | | | status | BUILD | | updated | 2014-06-10T00:01:05Z | | hostId | | | OS-EXT-SRV-ATTR:host | None | | key_name | key2 | | OS-EXT-SRV-ATTR:hypervisor_hostname | None | | name | cirros | | adminPass | oFRbvRqif2C8 | | tenant_id | 08cff06d13b74492b780d9ceed699239 | | created | 2014-06-10T00:01:04Z | | metadata | {} | +-------------------------------------+--------------------------------------+ ubuntu@node7:~$ ubuntu@node7:~$ nova list +--------------------------------------+--------+--------+----------+ | ID | Name | Status | Networks | +--------------------------------------+--------+--------+----------+ | 2eb5e3ad-3044-41c1-bbb7-10f398f83e43 | cirros | ERROR | | +--------------------------------------+--------+--------+----------+ ubuntu@node7:~$ var/log/nova/nova-compute.log shows the following error: ... 2014-06-10 00:01:06.048 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Attempting claim: memory 512 MB, disk 0 GB, VCPUs 1 2014-06-10 00:01:06.049 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Total Memory: 3885 MB, used: 512 MB 2014-06-10 00:01:06.049 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Memory limit: 5827 MB, free: 5315 MB 2014-06-10 00:01:06.049 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Total Disk: 146 GB, used: 0 GB 2014-06-10 00:01:06.050 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Disk limit not specified, defaulting to unlimited 2014-06-10 00:01:06.050 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Total CPU: 2 VCPUs, used: 0 VCPUs 2014-06-10 00:01:06.050 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] CPU limit not specified, defaulting to unlimited 2014-06-10 00:01:06.051 AUDIT nova.compute.claims [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Claim successful 2014-06-10 00:01:06.963 WARNING nova.network.quantumv2.api [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] No network configured! 2014-06-10 00:01:08.347 ERROR nova.compute.manager [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Instance failed to spawn 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Traceback (most recent call last): 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1118, in _spawn 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] self._legacy_nw_info(network_info), 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 703, in _legacy_nw_info 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] network_info = network_info.legacy() 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] AttributeError: 'list' object has no attribute 'legacy' 2014-06-10 00:01:08.347 32223 TRACE nova.compute.manager [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] 2014-06-10 00:01:08.919 AUDIT nova.compute.manager [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Terminating instance 2014-06-10 00:01:09.712 32223 ERROR nova.virt.libvirt.driver [-] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] During wait destroy, instance disappeared. 2014-06-10 00:01:09.718 INFO nova.virt.libvirt.firewall [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Attempted to unfilter instance which is not filtered 2014-06-10 00:01:09.719 INFO nova.virt.libvirt.driver [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Deleting instance files /var/lib/nova/instances/2eb5e3ad-3044-41c1-bbb7-10f398f83e43 2014-06-10 00:01:10.044 ERROR nova.compute.manager [req-41e53086-6454-4efb-bb35-a30dc2c780be b3730a52a32e40f0a9500440d1ef1c7d 08cff06d13b74492b780d9ceed699239] [instance: 2eb5e3ad-3044-41c1-bbb7-10f398f83e43] Error: ['Traceback (most recent call last):\n', ' File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 864, in _run_instance\n set_access_ip=set_access_ip)\n', ' File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1123, in _spawn\n LOG.exception(_(\'Instance failed to spawn\'), instance=instance)\n', ' File "/usr/lib/python2.7/contextlib.py", line 24, in __exit__\n self.gen.next()\n', ' File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1118, in _spawn\n self._legacy_nw_info(network_info),\n', ' File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 703, in _legacy_nw_info\n network_info = network_info.legacy()\n', "AttributeError: 'list' object has no attribute 'legacy'\n"] 2014-06-10 00:01:40.951 32223 AUDIT nova.compute.resource_tracker [-] Auditing locally available compute resources 2014-06-10 00:01:41.072 32223 AUDIT nova.compute.resource_tracker [-] Free ram (MB): 2861 2014-06-10 00:01:41.072 32223 AUDIT nova.compute.resource_tracker [-] Free disk (GB): 146 2014-06-10 00:01:41.073 32223 AUDIT nova.compute.resource_tracker [-] Free VCPUS: 1 2014-06-10 00:01:41.262 32223 INFO nova.compute.resource_tracker [-] Compute_service record updated for node5:node5.maas ... Can't seem to find any entries in quantum.conf related to "legacy". Any help would be appreciated. Cheers,

Read the article

Where'd My Data Go? (and/or...How Do I Get Rid of It?)

- by David Paquette

Want to get a better idea of how cascade deletes work in Entity Framework Code First scenarios? Want to see it in action? Stick with us as we quickly demystify what happens when you tell your data context to nuke a parent entity. This post is authored by Calgary .NET User Group Leader David Paquette with help from Microsoft MVP in Asp.Net James Chambers. We got to spend a great week back in March at Prairie Dev Con West, chalk full of sessions, presentations, workshops, conversations and, of course, questions. One of the questions that came up during my session: "How does Entity Framework Code First deal with cascading deletes?". James and I had different thoughts on what the default was, if it was different from SQL server, if it was the same as EF proper and if there was a way to override whatever the default was. So we built a set of examples and figured out that the answer is simple: it depends. (Download Samples) Consider the example of a hockey league. You have several different entities in the league including games, teams that play the games and players that make up the teams. Each team also has a mascot. If you delete a team, we need a couple of things to happen: The team, games and mascot will be deleted, and The players for that team will remain in the league (and therefore the database) but they should no longer be assigned to a team. So, let's make this start to come together with a look at the default behaviour in SQL when using an EDMX-driven project. The Reference – Understanding EF's Behaviour with an EDMX/DB First Approach First up let’s take a look at the DB first approach. In the database, we defined 4 tables: Teams, Players, Mascots, and Games. We also defined 4 foreign keys as follows: Players.Team_Id (NULL) –> Teams.Id Mascots.Id (NOT NULL) –> Teams.Id (ON DELETE CASCADE) Games.HomeTeam_Id (NOT NULL) –> Teams.Id Games.AwayTeam_Id (NOT NULL) –> Teams.Id Note that by specifying ON DELETE CASCADE for the Mascots –> Teams foreign key, the database will automatically delete the team’s mascot when the team is deleted. While we want the same behaviour for the Games –> Teams foreign keys, it is not possible to accomplish this using ON DELETE CASCADE in SQL Server. Specifying a ON DELETE CASCADE on these foreign keys would cause a circular reference error: The series of cascading referential actions triggered by a single DELETE or UPDATE must form a tree that contains no circular references. No table can appear more than one time in the list of all cascading referential actions that result from the DELETE or UPDATE – MSDN When we create an entity data model from the above database, we get the following: In order to get the Games to be deleted when the Team is deleted, we need to specify End1 OnDelete action of Cascade for the HomeGames and AwayGames associations. Now, we have an Entity Data Model that accomplishes what we set out to do. One caveat here is that Entity Framework will only properly handle the cascading delete when the the players and games for the team have been loaded into memory. For a more detailed look at Cascade Delete in EF Database First, take a look at this blog post by Alex James. Building The Same Sample with EF Code First Next, we're going to build up the model with the code first approach. EF Code First is defined on the Ado.Net team blog as such: Code First allows you to define your model using C# or VB.Net classes, optionally additional configuration can be performed using attributes on your classes and properties or by using a Fluent API. Your model can be used to generate a database schema or to map to an existing database. Entity Framework Code First follows some conventions to determine when to cascade delete on a relationship. More details can be found on MSDN: If a foreign key on the dependent entity is not nullable, then Code First sets cascade delete on the relationship. If a foreign key on the dependent entity is nullable, Code First does not set cascade delete on the relationship, and when the principal is deleted the foreign key will be set to null. The multiplicity and cascade delete behavior detected by convention can be overridden by using the fluent API. For more information, see Configuring Relationships with Fluent API (Code First). Our DbContext consists of 4 DbSets: public DbSet<Team> Teams { get; set; } public DbSet<Player> Players { get; set; } public DbSet<Mascot> Mascots { get; set; } public DbSet<Game> Games { get; set; } When we set the Mascot –> Team relationship to required, Entity Framework will automatically delete the Mascot when the Team is deleted. This can be done either using the [Required] data annotation attribute, or by overriding the OnModelCreating method of your DbContext and using the fluent API. Data Annotations: public class Mascot { public int Id { get; set; } public string Name { get; set; } [Required] public virtual Team Team { get; set; } } Fluent API: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Mascot>().HasRequired(m => m.Team); } The Player –> Team relationship is automatically handled by the Code First conventions. When a Team is deleted, the Team property for all the players on that team will be set to null. No additional configuration is required, however all the Player entities must be loaded into memory for the cascading to work properly. The Game –> Team relationship causes some grief in our Code First example. If we try setting the HomeTeam and AwayTeam relationships to required, Entity Framework will attempt to set On Cascade Delete for the HomeTeam and AwayTeam foreign keys when creating the database tables. As we saw in the database first example, this causes a circular reference error and throws the following SqlException: Introducing FOREIGN KEY constraint 'FK_Games_Teams_AwayTeam_Id' on table 'Games' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. To solve this problem, we need to disable the default cascade delete behaviour using the fluent API: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Mascot>().HasRequired(m => m.Team); modelBuilder.Entity<Team>() .HasMany(t => t.HomeGames) .WithRequired(g => g.HomeTeam) .WillCascadeOnDelete(false); modelBuilder.Entity<Team>() .HasMany(t => t.AwayGames) .WithRequired(g => g.AwayTeam) .WillCascadeOnDelete(false); base.OnModelCreating(modelBuilder); } Unfortunately, this means we need to manually manage the cascade delete behaviour. When a Team is deleted, we need to manually delete all the home and away Games for that Team. foreach (Game awayGame in jets.AwayGames.ToArray()) { entities.Games.Remove(awayGame); } foreach (Game homeGame in homeGames) { entities.Games.Remove(homeGame); } entities.Teams.Remove(jets); entities.SaveChanges(); Overriding the Defaults – When and How To As you have seen, the default behaviour of Entity Framework Code First can be overridden using the fluent API. This can be done by overriding the OnModelCreating method of your DbContext, or by creating separate model override files for each entity. More information is available on MSDN. Going Further These were simple examples but they helped us illustrate a couple of points. First of all, we were able to demonstrate the default behaviour of Entity Framework when dealing with cascading deletes, specifically how entity relationships affect the outcome. Secondly, we showed you how to modify the code and control the behaviour to get the outcome you're looking for. Finally, we showed you how easy it is to explore this kind of thing, and we're hoping that you get a chance to experiment even further. For example, did you know that: Entity Framework Code First also works seamlessly with SQL Azure (MSDN) Database creation defaults can be overridden using a variety of IDatabaseInitializers (Understanding Database Initializers) You can use Code Based migrations to manage database upgrades as your model continues to evolve (MSDN) Next Steps There's no time like the present to start the learning, so here's what you need to do: Get up-to-date in Visual Studio 2010 (VS2010 | SP1) or Visual Studio 2012 (VS2012) Build yourself a project to try these concepts out (or download the sample project) Get into the community and ask questions! There are a ton of great resources out there and community members willing to help you out (like these two guys!). Good luck! About the Authors David Paquette works as a lead developer at P2 Energy Solutions in Calgary, Alberta where he builds commercial software products for the energy industry. Outside of work, David enjoys outdoor camping, fishing, and skiing. David is also active in the software community giving presentations both locally and at conferences. David also serves as the President of Calgary .Net User Group. James Chambers crafts software awesomeness with an incredible team at LogiSense Corp, based in Cambridge, Ontario. A husband, father and humanitarian, he is currently residing in the province of Manitoba where he resists the urge to cheer for the Jets and maintains he allegiance to the Calgary Flames. When he's not active with the family, outdoors or volunteering, you can find James speaking at conferences and user groups across the country about web development and related technologies.

Read the article

SQL SERVER – Weekly Series – Memory Lane – #037

- by Pinal Dave

Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Convert Text to Numbers (Integer) – CAST and CONVERT If table column is VARCHAR and has all the numeric values in it, it can be retrieved as Integer using CAST or CONVERT function. List All Stored Procedure Modified in Last N Days If SQL Server suddenly start behaving in un-expectable behavior and if stored procedure were changed recently, following script can be used to check recently modified stored procedure. If a stored procedure was created but never modified afterwards modified date and create a date for that stored procedure are same. Count Duplicate Records – Rows Validate Field For DATE datatype using function ISDATE() We always checked DATETIME field for incorrect data type. One of the user input date as 30/2/2007. The date was sucessfully inserted in the temp table but while inserting from temp table to final table it crashed with error. We had now task to validate incorrect date value before we insert in final table. Jr. Developer asked me how can he do that? We check for incorrect data type (varchar, int, NULL) but this is incorrect date value. Regular expression works fine with them because of mm/dd/yyyy format. 2008 Find Space Used For Any Particular Table It is very simple to find out the space used by any table in the database. Two Convenient Features Inline Assignment – Inline Operations Here is the script which does both – Inline Assignment and Inline Operation DECLARE @idx INT = 0 SET @idx+=1 SELECT @idx Introduction to SPARSE Columns SPARSE column are better at managing NULL and ZERO values in SQL Server. It does not take any space in database at all. If column is created with SPARSE clause with it and it contains ZERO or NULL it will be take lesser space then regular column (without SPARSE clause). SP_CONFIGURE – Displays or Changes Global Configuration Settings If advanced settings are not enabled at configuration level SQL Server will not let user change the advanced features on server. Authorized user can turn on or turn off advance settings. 2009 Standby Servers and Types of Standby Servers Standby Server is a type of server that can be brought online in a situation when Primary Server goes offline and application needs continuous (high) availability of the server. There is always a need to set up a mechanism where data and objects from primary server are moved to secondary (standby) server. BLOB – Pointer to Image, Image in Database, FILESTREAM Storage When it comes to storing images in database there are two common methods. I had previously blogged about the same subject on my visit to Toronto. With SQL Server 2008, we have a new method of FILESTREAM storage. However, the answer on when to use FILESTREAM and when to use other methods is still vague in community. 2010 Upper Case Shortcut SQL Server Management Studio I select the word and hit CTRL+SHIFT+U and it SSMS immediately changes the case of the selected word. Similar way if one want to convert cases to lower case, another short cut CTRL+SHIFT+L is also available. The Self Join – Inner Join and Outer Join Self Join has always been a noteworthy case. It is interesting to ask questions about self join in a room full of developers. I often ask – if there are three kinds of joins, i.e.- Inner Join, Outer Join and Cross Join; what type of join is Self Join? The usual answer is that it is an Inner Join. However, the reality is very different. Parallelism – Row per Processor – Row per Thread – Thread 0 If you look carefully in the Properties window or XML Plan, there is “Thread 0?. What does this “Thread 0” indicate? Well find out from the blog post. How do I Learn and How do I Teach The blog post has raised three very interesting questions. How do you learn? How do you teach? What are you learning or teaching? Let me try to answer the same. 2011 SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 7 of 31 What are Different Types of Locks? What are Pessimistic Lock and Optimistic Lock? When is the use of UPDATE_STATISTICS command? What is the Difference between a HAVING clause and a WHERE clause? What is Connection Pooling and why it is Used? What are the Properties and Different Types of Sub-Queries? What are the Authentication Modes in SQL Server? How can it be Changed? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 8 of 31 Which Command using Query Analyzer will give you the Version of SQL Server and Operating System? What is an SQL Server Agent? Can a Stored Procedure call itself or a Recursive Stored Procedure? How many levels of SP nesting is possible? What is Log Shipping? Name 3 ways to get an Accurate Count of the Number of Records in a Table? What does it mean to have QUOTED_IDENTIFIER ON? What are the Implications of having it OFF? What is the Difference between a Local and a Global Temporary Table? What is the STUFF Function and How Does it Differ from the REPLACE Function? What is PRIMARY KEY? What is UNIQUE KEY Constraint? What is FOREIGN KEY? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 9 of 31 What is CHECK Constraint? What is NOT NULL Constraint? What is the difference between UNION and UNION ALL? What is B-Tree? How to get @@ERROR and @@ROWCOUNT at the Same Time? What is a Scheduled Job or What is a Scheduled Task? What are the Advantages of Using Stored Procedures? What is a Table Called, if it has neither Cluster nor Non-cluster Index? What is it Used for? Can SQL Servers Linked to other Servers like Oracle? What is BCP? When is it Used? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 10 of 31 What Command do we Use to Rename a db, a Table and a Column? What are sp_configure Commands and SET Commands? How to Implement One-to-One, One-to-Many and Many-to-Many Relationships while Designing Tables? What is Difference between Commit and Rollback when Used in Transactions? What is an Execution Plan? When would you Use it? How would you View the Execution Plan? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 11 of 31 What is Difference between Table Aliases and Column Aliases? Do they Affect Performance? What is the difference between CHAR and VARCHAR Datatypes? What is the Difference between VARCHAR and VARCHAR(MAX) Datatypes? What is the Difference between VARCHAR and NVARCHAR datatypes? Which are the Important Points to Note when Multilanguage Data is Stored in a Table? How to Optimize Stored Procedure Optimization? What is SQL Injection? How to Protect Against SQL Injection Attack? How to Find Out the List Schema Name and Table Name for the Database? What is CHECKPOINT Process in the SQL Server? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 12 of 31 How does Using a Separate Hard Drive for Several Database Objects Improves Performance Right Away? How to Find the List of Fixed Hard Drive and Free Space on Server? Why can there be only one Clustered Index and not more than one? What is Difference between Line Feed (\n) and Carriage Return (\r)? Is It Possible to have Clustered Index on Separate Drive From Original Table Location? What is a Hint? How to Delete Duplicate Rows? Why the Trigger Fires Multiple Times in Single Login? 2012 CTRL+SHIFT+] Shortcut to Select Code Between Two Parenthesis Shortcut key is CTRL+SHIFT+]. This key can be very useful when dealing with multiple subqueries, CTE or query with multiple parentheses. When exercised this shortcut key it selects T-SQL code between two parentheses. Monday Morning Puzzle – Query Returns Results Sometimes but Not Always I am beginner with SQL Server. I have one query, it sometime returns a result and sometime it does not return me the result. Where should I start looking for a solution and what kind of information I should send to you so you can help me with solving. I have no clue, please guide me. Remove Debug Button in SSMS – SQL in Sixty Seconds #020 – Video Effect of Case Sensitive Collation on Resultset Collation is a very interesting concept but I quite often see it is heavily neglected. I have seen developer and DBA looking for a workaround to fix collation error rather than understanding if the side effect of the workaround. Switch Between Two Parenthesis using Shortcut CTRL+] Earlier this week I wrote a blog post about CTRL+SHIFT+] Shortcut to Select Code Between Two Parenthesis, I received quite a lot of positive feedback from readers. If you are a regular reader of the blog post, you must be aware that I appreciate the learning shared by readers. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

Read the article

How Mature is Your Database Change Management Process?

- by Ben Rees

.dbd-banner p{ font-size:0.75em; padding:0 0 10px; margin:0 } .dbd-banner p span{ color:#675C6D; } .dbd-banner p:last-child{ padding:0; } @media ALL and (max-width:640px){ .dbd-banner{ background:#f0f0f0; padding:5px; color:#333; margin-top: 5px; } } -- Database Delivery Patterns & Practices Further Reading Organization and team processes How do you get your database schema changes live, on to your production system? As your team of developers and DBAs are working on the changes to the database to support your business-critical applications, how do these updates wend their way through from dev environments, possibly to QA, hopefully through pre-production and eventually to production in a controlled, reliable and repeatable way? In this article, I describe a model we use to try and understand the different stages that customers go through as their database change management processes mature, from the very basic and manual, through to advanced continuous delivery practices. I also provide a simple chart that will help you determine “How mature is our database change management process?” This process of managing changes to the database – which all of us who have worked in application/database development have had to deal with in one form or another – is sometimes known as Database Change Management (even if we’ve never used the term ourselves). And it’s a difficult process, often painfully so. Some developers take the approach of “I’ve no idea how my changes get live – I just write the stored procedures and add columns to the tables. It’s someone else’s problem to get this stuff live. I think we’ve got a DBA somewhere who deals with it – I don’t know, I’ve never met him/her”. I know I used to work that way. I worked that way because I assumed that making the updates to production was a trivial task – how hard can it be? Pause the application for half an hour in the middle of the night, copy over the changes to the app and the database, and switch it back on again? Voila! But somehow it never seemed that easy. And it certainly was never that easy for database changes. Why? Because you can’t just overwrite the old database with the new version. Databases have a state – more specifically 4Tb of critical data built up over the last 12 years of running your business, and if your quick hotfix happened to accidentally delete that 4Tb of data, then you’re “Looking for a new role” pretty quickly after the failed release. There are a lot of other reasons why a managed database change management process is important for organisations, besides job security, not least: Frequency of releases. Many business managers are feeling the pressure to get functionality out to their users sooner, quicker and more reliably. The new book (which I highly recommend) Lean Enterprise by Jez Humble, Barry O’Reilly and Joanne Molesky provides a great discussion on how many enterprises are having to move towards a leaner, more frequent release cycle to maintain their competitive advantage. It’s no longer acceptable to release once per year, leaving your customers waiting all year for changes they desperately need (and expect) Auditing and compliance. SOX, HIPAA and other compliance frameworks have demanded that companies implement proper processes for managing changes to their databases, whether managing schema changes, making sure that the data itself is being looked after correctly or other mechanisms that provide an audit trail of changes. We’ve found, at Red Gate that we have a very wide range of customers using every possible form of database change management imaginable. Everything from “Nothing – I just fix the schema on production from my laptop when things go wrong, and write it down in my notebook” to “A full Continuous Delivery process – any change made by a dev gets checked in and recorded, fully tested (including performance tests) before a (tested) release is made available to our Release Management system, ready for live deployment!”. And everything in between of course. Because of the vast number of customers using so many different approaches we found ourselves struggling to keep on top of what everyone was doing – struggling to identify patterns in customers’ behavior. This is useful for us, because we want to try and fit the products we have to different needs – different products are relevant to different customers and we waste everyone’s time (most notably, our customers’) if we’re suggesting products that aren’t appropriate for them. If someone visited a sports store, looking to embark on a new fitness program, and the store assistant suggested the latest $10,000 multi-gym, complete with multiple weights mechanisms, dumb-bells, pull-up bars and so on, then he’s likely to lose that customer. All he needed was a pair of running shoes! To solve this issue – in an attempt to simplify how we understand our customers and our offerings – we built a model. This is a an attempt at trying to classify our customers in to some sort of model or “Customer Maturity Framework” as we rather grandly term it, which somehow simplifies our understanding of what our customers are doing. The great statistician, George Box (amongst other things, the “Box” in the Box-Jenkins time series model) gave us the famous quote: “Essentially all models are wrong, but some are useful” We’ve taken this quote to heart – we know it’s a gross over-simplification of the real world of how users work with complex legacy and new database developments. Almost nobody precisely fits in to one of our categories. But we hope it’s useful and interesting. There are actually a number of similar models that exist for more general application delivery. We’ve found these from ThoughtWorks/Forrester, from InfoQ and others, and initially we tried just taking these models and replacing the word “application” for “database”. However, we hit a problem. From talking to our customers we know that users are far less further down the road of mature database change management than they are for application development. As a simple example, no application developer, who wants to keep his/her job would develop an application for an organisation without source controlling that code. Sure, he/she might not be using an advanced Gitflow branching methodology but they’ll certainly be making sure their code gets managed in a repo somewhere with all the benefits of history, auditing and so on. But this certainly isn’t the case (yet) for the database – a very large segment of the people we speak to have no source control set up for their databases whatsoever, even at the most basic level (for example, keeping change scripts in a source control system somewhere). By the way, if this is you, Red Gate has a great whitepaper here, on the barriers people face getting a source control process implemented at their organisations. This difference in maturity is the same as you move in to areas such as continuous integration (common amongst app developers, relatively rare for database developers) and automated release management (growing amongst app developers, very rare for the database). So, when we created the model we started from scratch and biased the levels of maturity towards what we actually see amongst our customers. But, what are these stages? And what level are you? The table below describes our definitions for four levels of maturity – Baseline, Beginner, Intermediate and Advanced. As I say, this is a model – you won’t fit any of these categories perfectly, but hopefully one will ring true more than others. We’ve also created a PDF with a flow chart to help you find which of these groups most closely matches your team: Download the Database Delivery Maturity Framework PDF here Level D1 – Baseline Work directly on live databases Sometimes work directly in production Generate manual scripts for releases. Sometimes use a product like SQL Compare or similar to do this Any tests that we might have are run manually Level D2 – Beginner Have some ad-hoc DB version control such as manually adding upgrade scripts to a version control system Attempt is made to keep production in sync with development environments There is some documentation and planning of manual deployments Some basic automated DB testing in process Level D3 – Intermediate The database is fully version-controlled with a product like Red Gate SQL Source Control or SSDT Database environments are managed Production environment schema is reproducible from the source control system There are some automated tests Have looked at using migration scripts for difficult database refactoring cases Level D4 – Advanced Using continuous integration for database changes Build, testing and deployment of DB changes carried out through a proper database release process Fully automated tests Production system is monitored for fast feedback to developers Does this model reflect your team at all? Where are you on this journey? We’d be very interested in knowing how you get on. We’re doing a lot of work at the moment, at Red Gate, trying to help people progress through these stages. For example, if you’re currently not source controlling your database, then this is a natural next step. If you are already source controlling your database, what about the next stage – continuous integration and automated release management? To help understand these issues, there’s a summary of the Red Gate Database Delivery learning program on our site, alongside a Patterns and Practices library here on Simple-Talk and a Training Academy section on our documentation site to help you get up and running with the tools you need to progress. All feedback is welcome and it would be great to hear where you find yourself on this journey! This article is part of our database delivery patterns & practices series on Simple Talk. Find more articles for version control, automated testing, continuous integration & deployment.

Read the article

Building applications with WCF - Intro

- by skjagini

I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had to derive from EF specific base classes. In EF 4 it is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks. Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System; namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } } In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity; namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } } Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information. using System; using System.Data.Entity.ModelConfiguration; namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); } private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id); //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } } Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context. We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers; public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; } public IQueryable<Customer> Query() { return _customers; } public void Add(Customer customer) { _customers.Add(customer); } } } From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods. Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts; public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; } public IQueryable<CheckingAccount> Query() { return _checkingAccounts; } public void Add(CheckingAccount account) { _checkingAccounts.Add(account); } public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); } } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details. using System; using System.ServiceModel; using BankDAL.Model; namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth); [OperationContract] Customer GetCustomer(int id); } } ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account. using System.ServiceModel; namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId); [OperationContract] void DepositAmount(int customerId,decimal amount); [OperationContract] void WithdrawAmount(int customerId, decimal amount); } } Services Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract; namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth }; using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; } public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); } } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract; namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault(); if (account != null) return account.Balance; return null; } } public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault(); if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); } account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted"); bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } } BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients. using System; namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); } private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); } private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open(); if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files. <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> </client> </system.serviceModel> The client uses a façade to connect to the services using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract; namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); } public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); } public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); } } } With that in place, lets get our unit tests going using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract; namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); } private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); } [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); } [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); } [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss"); var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id; ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); } Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } } We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account. Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling. Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

Read the article

Hudson on debian lenny

- by Laurent

Hello, I installed Hudson deamon on one server (running on debian lenny testing) some time ago. All was working until I perform an upgrade. At this time Hudson isn't accessible at port 8080 (which is the default port used). I have looked for iptables problems, however port 8080 is open in INPUT and OUTPUT. Configuration file in /etc/default/hudson seems okay, I haven't touch it. And if I do a ps aux | grep hudson, hudson deamon is running. Update 1: What is really strange for me is that in /var/log/hudson/hudson.log I get no error : [Winstone 2010/02/10 17:10:04] - Control thread shutdown successfully [Winstone 2010/02/10 17:10:04] - Winstone shutdown successfully Running from: /usr/share/hudson/hudson.war [Winstone 2010/02/10 17:10:43] - Beginning extraction from war file hudson home directory: /var/lib/hudson [Winstone 2010/02/10 17:10:44] - HTTP Listener started: port=8080 [Winstone 2010/02/10 17:10:44] - AJP13 Listener started: port=8009 [Winstone 2010/02/10 17:10:44] - Winstone Servlet Engine v0.9.10 running: controlPort=disabled 10 févr. 2010 17:10:44 hudson.model.Hudson$4 onAttained INFO: Started initialization 10 févr. 2010 17:10:44 hudson.model.Hudson$4 onAttained INFO: Listed all plugins 10 févr. 2010 17:10:44 hudson.model.Hudson$4 onAttained INFO: Prepared all plugins 10 févr. 2010 17:10:44 hudson.model.Hudson$4 onAttained INFO: Started all plugins 10 févr. 2010 17:10:46 hudson.model.Hudson$4 onAttained INFO: Loaded all jobs 10 févr. 2010 17:10:46 hudson.model.Hudson$4 onAttained INFO: Completed initialization 10 févr. 2010 17:10:47 org.springframework.context.support.AbstractApplicationContext prepareRefresh INFO: Refreshing org.springframework.web.context.support.StaticWebApplicationContext@caa559d: display name [Root WebApplicationContext]; startup date [Wed Feb 10 17:10:47 CET 2010]; root of context hierarchy 10 févr. 2010 17:10:47 org.springframework.context.support.AbstractApplicationContext obtainFreshBeanFactory INFO: Bean factory for application context [org.springframework.web.context.support.StaticWebApplicationContext@caa559d]: org.springframework.beans.factory.support.DefaultListableBeanFactory@40d2f5f1 10 févr. 2010 17:10:47 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@40d2f5f1: defining beans [daoAuthenticationProvider,authenticationManager,userDetailsService]; root of factory hierarchy 10 févr. 2010 17:10:47 org.springframework.context.support.AbstractApplicationContext prepareRefresh INFO: Refreshing org.springframework.web.context.support.StaticWebApplicationContext@4d88a387: display name [Root WebApplicationContext]; startup date [Wed Feb 10 17:10:47 CET 2010]; root of context hierarchy 10 févr. 2010 17:10:47 org.springframework.context.support.AbstractApplicationContext obtainFreshBeanFactory INFO: Bean factory for application context [org.springframework.web.context.support.StaticWebApplicationContext@4d88a387]: org.springframework.beans.factory.support.DefaultListableBeanFactory@6153e0c0 10 févr. 2010 17:10:47 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@6153e0c0: defining beans [filter,legacy]; root of factory hierarchy 10 févr. 2010 17:10:47 hudson.TcpSlaveAgentListener <init> INFO: JNLP slave agent listener started on TCP port 59750 Update 2: What I get with lsof -i -n -P | grep hudson: java 28985 hudson 97u IPv6 2002707 0t0 TCP *:8080 (LISTEN) java 28985 hudson 99u IPv6 2002708 0t0 TCP *:8009 (LISTEN) java 28985 hudson 147u IPv6 2002711 0t0 TCP *:59750 (LISTEN) java 28985 hudson 150u IPv6 2002712 0t0 UDP *:33848 I don't know what I can verify. Does someone has an idea in order to help me to resolve this problem ?

Read the article

Apache mod_jk Setting for Tomcat - workers.properties

- by sissonb

I am trying to direct files with .jsp extensions to tomcat. Otherwise I want apache to serve the file directly (no tomcat). Currently I have a test.jsp which is supposed to create an HTML page with the current date in the body. Instead when I go to that .jsp I see the JK Status Manager. The mod_jk.logs only show, init_jk::mod_jk.c (3365): mod_jk/1.2.35 initialized. I have tomcat and apache setup on my server. Apache runs on 80 and tomcat runs on 8080. localhost:8080 show the tomcat welcome page. I downloaded tomcat-connectors-1.2.35-windows-i386-httpd-2.2.x and copied the mod_jk.so to C:\apache\modules. Then I added LoadModule jk_module modules/mod_jk.so to my httpd.conf. I restart apache and the module loads just fine. Next I downloaded the mod_jk source to get the workers.properties file. I copy workers.properties to C:\apache\confg. Then I added this user, workers.tomcat_home="C:/Program Files/Apache Software Foundation/Tomcat 7.0" workers.java_home="C:/Program Files/Java/jdk1.7.0_03" worker.list=ajp13 worker.ajp13.port=8080 worker.ajp13.host=localhost worker.ajp13.type=ajp13 worker.ajp13.socket_timeout=10 When I try to use the ajp13 user in my httpd.conf I get the following error in my mod_jk.log, [Wed Mar 28 13:08:51 2012] [2196:4100] [info] ajp_connection_tcp_get_message::jk_ajp_common.c (1258): (ajp13) can't receive the response header message from tomcat, network problems or tomcat (127.0.0.1:8080) is down (errno=60) [Wed Mar 28 13:08:51 2012] [2196:4100] [error] ajp_get_reply::jk_ajp_common.c (2117): (ajp13) Tomcat is down or refused connection. No response has been sent to the client (yet) [Wed Mar 28 13:08:51 2012] [2196:4100] [info] ajp_service::jk_ajp_common.c (2614): (ajp13) sending request to tomcat failed (recoverable), (attempt=1) Next I update my httpd.conf with, JkWorkersFile C:/apache/conf/workers.properties JkLogFile C:/apache/logs/mod_jk.log JkLogLevel info JkLogStampFormat "[%a %b %d %H:%M:%S %Y] " Also I added JkMount /*.jsp jk-status to my virtual host like this, <VirtualHost 192.168.5.250:80> JkMount /*.jsp jk-status #JkMount /*.jsp ajp13 ServerName bgsisson.com ServerAlias www.bgsisson.com DocumentRoot C:/www/resume </VirtualHost> I think i need to include a uriworkermap.properties file, but this is where I am getting stuck. I have put up a test .jsp at bgsisson.com/test.jsp It shows the JK Status Manager when I use JkMount /*.jsp jk-status and 502 Bad Gateway when I use JkMount /*.jsp ajp13 test.jsp <%-- use the 'taglib' directive to make the JSTL 1.0 core tags available; use the uri "http://java.sun.com/jsp/jstl/core" for JSTL 1.1 --%> <%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %> <%-- use the 'jsp:useBean' standard action to create the Date object; the object is set as an attribute in page scope --%> <jsp:useBean id="date" class="java.util.Date" /> <html> <head><title>First JSP</title></head> <body> <h2>Here is today's date</h2> <c:out value="${date}" /> </body> </html>

Read the article

Minecraft server Rkit ubuntu upstart [closed]

- by user1637491

I have an Intel server running Ubuntu Server 12.04.1 I am working on moving my CraftBukkit Minecraft Server to the new platform. I read the upstart ubuntu cookbook and wrote a .conf file I have a minecraft user (named minecraft) and its home Directory is /home/minecraft it contains prwxrwxrwx 1 minecraft minecraft 0 Sep 19 14:49 command-fifo drwx------ 8 minecraft minecraft 4096 Sep 19 14:50 HDsaves drwx------ 2 minecraft minecraft 4096 Aug 31 15:13 logrolls -rw-r--r-- 1 root root 5 Sep 19 14:49 minecraft.pid drwxrwxrwx 8 minecraft minecraft 180 Sep 19 14:49 ramdisk -rw------- 1 minecraft minecraft 119 Sep 19 10:34 save.sh drwxrwxrwx 9 minecraft minecraft 4096 Sep 19 14:50 server -rw-rw-r-- 1 minecraft minecraft 44 Aug 31 11:40 shutdown.sh the server directory contains drwxrwxrwx 6 minecraft minecraft 4096 Aug 30 13:32 Backups -rwxrwxrwx 1 minecraft minecraft 0 Sep 18 12:26 banned-ips.txt -rwxrwxrwx 1 minecraft minecraft 17 Sep 18 12:26 banned-players.txt drwxrwxrwx 4 minecraft minecraft 4096 Aug 30 12:26 buildcraft -rwxrwxrwx 1 minecraft minecraft 1447 Sep 18 12:26 bukkit.yml -rwxrwxrwx 1 minecraft minecraft 0 Aug 30 11:05 command-fifo drwxrwxrwx 2 minecraft minecraft 4096 Aug 30 12:26 config lrwxrwxrwx 1 minecraft minecraft 23 Sep 19 14:49 craftbukkit.jar -> ramdisk/craftbukkit.jar -rwxrwxrwx 1 minecraft minecraft 17419 Sep 18 12:26 ForgeModLoader-0.log -rwxrwxrwx 1 minecraft minecraft 17420 Sep 18 12:24 ForgeModLoader-1.log -rwxrwxrwx 1 minecraft minecraft 17420 Sep 18 11:53 ForgeModLoader-2.log -rwxrwxrwx 1 minecraft minecraft 2576 Aug 30 11:05 help.yml drwxrwxrwx 2 minecraft minecraft 4096 Aug 30 12:31 lib drwxrwxrwx 3 minecraft minecraft 4096 Sep 19 14:49 logrolls -rwxrwxrwx 1 minecraft minecraft 200035 Sep 4 17:58 Minecraft_RKit.jar lrwxrwxrwx 1 minecraft minecraft 12 Sep 19 14:49 mods -> ramdisk/mods -rwxrwxrwx 1 minecraft minecraft 5 Sep 18 12:26 ops.txt -rwxrwxrwx 1 minecraft minecraft 0 Aug 30 11:05 permissions.yml lrwxrwxrwx 1 minecraft minecraft 15 Sep 19 14:49 plugins -> ramdisk/plugins lrwxrwxrwx 1 minecraft minecraft 16 Sep 19 14:49 redpower -> ramdisk/redpower -rw-r--r-- 1 root root 255 Sep 19 15:10 server.log -rwxrwxrwx 1 minecraft minecraft 464 Sep 8 11:09 server.properties drwxrwxrwx 3 minecraft minecraft 4096 Sep 5 16:05 SpaceModule drwxrwxrwx 3 minecraft minecraft 4096 Aug 30 13:07 toolkit -rwxrwxrwx 1 minecraft minecraft 1433 Sep 14 21:04 wepif.yml -rwxrwxrwx 1 minecraft minecraft 0 Sep 18 12:26 white-list.txt lrwxrwxrwx 1 minecraft minecraft 13 Sep 19 14:49 world -> ramdisk/world lrwxrwxrwx 1 minecraft minecraft 20 Sep 19 14:49 world_nether -> ramdisk/world_nether lrwxrwxrwx 1 minecraft minecraft 21 Sep 19 14:49 world_the_end -> ramdisk/world_the_end the startup .conf file: # Starts the minecraft server after loading JRE from ramdisk # # for now im still working on it description "minecraft-server" start on filesystem or runlevel [2345] stop on runlevel [!2345] oom score -999 kill timeout 60 pre-start script sh /usr/lib/jvm/java.sh end script script cd /home/minecraft echo "$(date) Starting minecraft" sudo cp -r /home/minecraft/HDsaves/* ramdisk sudo chown -R minecraft:minecraft ramdisk sudo chmod -R 777 ramdisk sudo ln -sf ramdisk/* server sudo chown -R minecraft:minecraft server sudo chmod -R 777 server sudo mv server/server.log server/logrolls/ zip server/logrolls/temp.zip server/logrolls/server.log sudo mv server/logrolls/temp.zip server/logrolls/"$(date)".log.zip sudo rm server/logrolls/server.log sudo rm -f command-fifo sudo mkfifo command-fifo sudo chown minecraft:minecraft command-fifo sudo chmod 777 command-fifo echo "$(date) Root commands finished" echo "$(date) Starting Wrapper" cd server sudo -u minecraft java -Xmx30M -Xms30M -XX:MaxPermSize=40M -Djava.awt.headless=true -jar Minecraft_RKit.jar timv:*spoilers* <> /home/minecraft/command-fifo & sudo echo $! >| /home/minecraft/minecraft.pid echo "$(date) Minecraft Started" end script pre-stop script cd /home/minecraft PID=`cat minecraft.pid` if [ "$PID" != "" ]; then echo "Stopping MineCraft Server PID=$PID" sudo echo save-all >> command-fifo sudo echo .stopwrapper >> command-fifo wait $PID sudo rm minecraft.pid sudo rsync -rt --delete ramdisk/* HDsaves/ echo "$(date) ramdisk save complete" echo "MineCraft save-shutdown complete." else echo "MineCraft not running" fi end script so when I start it up the upstart gererated log says: Wed Sep 19 14:49:30 CDT 2012 Starting minecraft adding: server/logrolls/server.log (stored 0%) Wed Sep 19 14:49:56 CDT 2012 Root commands finished Wed Sep 19 14:49:56 CDT 2012 Starting Wrapper Wed Sep 19 14:49:56 CDT 2012 Minecraft Started

Read the article

LINQ to SQL and missing Many to Many EntityRefs

- by Rick Strahl

Ran into an odd behavior today with a many to many mapping of one of my tables in LINQ to SQL. Many to many mappings aren’t transparent in LINQ to SQL and it maps the link table the same way the SQL schema has it when creating one. In other words LINQ to SQL isn’t smart about many to many mappings and just treats it like the 3 underlying tables that make up the many to many relationship. Iain Galloway has a nice blog entry about Many to Many relationships in LINQ to SQL. I can live with that – it’s not really difficult to deal with this arrangement once mapped, especially when reading data back. Writing is a little more difficult as you do have to insert into two entities for new records, but nothing that can’t be handled in a small business object method with a few lines of code. When I created a database I’ve been using to experiment around with various different OR/Ms recently I found that for some reason LINQ to SQL was completely failing to map even to the linking table. As it turns out there’s a good reason why it fails, can you spot it below? (read on :-}) Here is the original database layout: There’s an items table, a category table and a link table that holds only the foreign keys to the Items and Category tables for a typical M->M relationship. When these three tables are imported into the model the *look* correct – I do get the relationships added (after modifying the entity names to strip the prefix): The relationship looks perfectly fine, both in the designer as well as in the XML document: <Table Name="dbo.wws_Item_Categories" Member="ItemCategories"> <Type Name="ItemCategory"> <Column Name="ItemId" Type="System.Guid" DbType="uniqueidentifier NOT NULL" CanBeNull="false" /> <Column Name="CategoryId" Type="System.Guid" DbType="uniqueidentifier NOT NULL" CanBeNull="false" /> <Association Name="ItemCategory_Category" Member="Categories" ThisKey="CategoryId" OtherKey="Id" Type="Category" /> <Association Name="Item_ItemCategory" Member="Item" ThisKey="ItemId" OtherKey="Id" Type="Item" IsForeignKey="true" /> </Type> </Table> <Table Name="dbo.wws_Categories" Member="Categories"> <Type Name="Category"> <Column Name="Id" Type="System.Guid" DbType="UniqueIdentifier NOT NULL" IsPrimaryKey="true" IsDbGenerated="true" CanBeNull="false" /> <Column Name="ParentId" Type="System.Guid" DbType="UniqueIdentifier" CanBeNull="true" /> <Column Name="CategoryName" Type="System.String" DbType="NVarChar(150)" CanBeNull="true" /> <Column Name="CategoryDescription" Type="System.String" DbType="NVarChar(MAX)" CanBeNull="true" /> <Column Name="tstamp" AccessModifier="Internal" Type="System.Data.Linq.Binary" DbType="rowversion" CanBeNull="true" IsVersion="true" /> <Association Name="ItemCategory_Category" Member="ItemCategory" ThisKey="Id" OtherKey="CategoryId" Type="ItemCategory" IsForeignKey="true" /> </Type> </Table> However when looking at the code generated these navigation properties (also on Item) are completely missing: [global::System.Data.Linq.Mapping.TableAttribute(Name="dbo.wws_Item_Categories")] [global::System.Runtime.Serialization.DataContractAttribute()] public partial class ItemCategory : Westwind.BusinessFramework.EntityBase { private System.Guid _ItemId; private System.Guid _CategoryId; public ItemCategory() { } [global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_ItemId", DbType="uniqueidentifier NOT NULL")] [global::System.Runtime.Serialization.DataMemberAttribute(Order=1)] public System.Guid ItemId { get { return this._ItemId; } set { if ((this._ItemId != value)) { this._ItemId = value; } } } [global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_CategoryId", DbType="uniqueidentifier NOT NULL")] [global::System.Runtime.Serialization.DataMemberAttribute(Order=2)] public System.Guid CategoryId { get { return this._CategoryId; } set { if ((this._CategoryId != value)) { this._CategoryId = value; } } } } Notice that the Item and Category association properties which should be EntityRef properties are completely missing. They’re there in the model, but the generated code – not so much. So what’s the problem here? The problem – it appears – is that LINQ to SQL requires primary keys on all entities it tracks. In order to support tracking – even of the link table entity – the link table requires a primary key. Real obvious ain’t it, especially since the designer happily lets you import the table and even shows the relationship and implicitly the related properties. Adding an Id field as a Pk to the database and then importing results in this model layout: which properly generates the Item and Category properties into the link entity. It’s ironic that LINQ to SQL *requires* the PK in the middle – the Entity Framework requires that a link table have *only* the two foreign key fields in a table in order to recognize a many to many relation. EF actually handles the M->M relation directly without the intermediate link entity unlike LINQ to SQL. [updated from comments – 12/24/2009] Another approach is to set up both ItemId and CategoryId in the database which shows up in LINQ to SQL like this: This also work in creating the Category and Item fields in the ItemCategory entity. Ultimately this is probably the best approach as it also guarantees uniqueness of the keys and so helps in database integrity. It took me a while to figure out WTF was going on here – lulled by the designer to think that the properties should be when they were not. It’s actually a well documented feature of L2S that each entity in the model requires a Pk but of course that’s easy to miss when the model viewer shows it to you and even the underlying XML model shows the Associations properly. This is one of the issue with L2S of course – you have to play by its rules and once you hit one of those rules there’s no way around them – you’re stuck with what it requires which in this case meant changing the database.© Rick Strahl, West Wind Technologies, 2005-2010Posted in ADO.NET LINQ

Read the article

Securing an ASP.NET MVC 2 Application

- by rajbk

This post attempts to look at some of the methods that can be used to secure an ASP.NET MVC 2 Application called Northwind Traders Human Resources. The sample code for the project is attached at the bottom of this post. We are going to use a slightly modified Northwind database. The screen capture from SQL server management studio shows the change. I added a new column called Salary, inserted some random salaries for the employees and then turned off AllowNulls. The reporting relationship for Northwind Employees is shown below. The requirements for our application are as follows: Employees can see their LastName, FirstName, Title, Address and Salary Employees are allowed to edit only their Address information Employees can see the LastName, FirstName, Title, Address and Salary of their immediate reports Employees cannot see records of non immediate reports. Employees are allowed to edit only the Salary and Title information of their immediate reports. Employees are not allowed to edit the Address of an immediate report Employees should be authenticated into the system. Employees by default get the “Employee” role. If a user has direct reports, they will also get assigned a “Manager” role. We use a very basic empId/pwd scheme of EmployeeID (1-9) and password test$1. You should never do this in an actual application. The application should protect from Cross Site Request Forgery (CSRF). For example, Michael could trick Steven, who is already logged on to the HR website, to load a page which contains a malicious request. where without Steven’s knowledge, a form on the site posts information back to the Northwind HR website using Steven’s credentials. Michael could use this technique to give himself a raise :-) UI Notes The layout of our app looks like so: When Nancy (EmpID 1) signs on, she sees the default page with her details and is allowed to edit her address. If Nancy attempts to view the record of employee Andrew who has an employeeID of 2 (Employees/Edit/2), she will get a “Not Authorized” error page. When Andrew (EmpID 2) signs on, he can edit the address field of his record and change the title and salary of employees that directly report to him. Implementation Notes All controllers inherit from a BaseController. The BaseController currently only has error handling code. When a user signs on, we check to see if they are in a Manager role. We then create a FormsAuthenticationTicket, encrypt it (including the roles that the employee belongs to) and add it to a cookie. private void SetAuthenticationCookie(int employeeID, List<string> roles) { HttpCookiesSection cookieSection = (HttpCookiesSection) ConfigurationManager.GetSection("system.web/httpCookies"); AuthenticationSection authenticationSection = (AuthenticationSection) ConfigurationManager.GetSection("system.web/authentication"); FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket( 1, employeeID.ToString(), DateTime.Now, DateTime.Now.AddMinutes(authenticationSection.Forms.Timeout.TotalMinutes), false, string.Join("|", roles.ToArray())); String encryptedTicket = FormsAuthentication.Encrypt(authTicket); HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket); if (cookieSection.RequireSSL || authenticationSection.Forms.RequireSSL) { authCookie.Secure = true; } HttpContext.Current.Response.Cookies.Add(authCookie); } We read this cookie back in Global.asax and set the Context.User to be a new GenericPrincipal with the roles we assigned earlier. protected void Application_AuthenticateRequest(Object sender, EventArgs e){ if (Context.User != null) { string cookieName = FormsAuthentication.FormsCookieName; HttpCookie authCookie = Context.Request.Cookies[cookieName]; if (authCookie == null) return; FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value); string[] roles = authTicket.UserData.Split(new char[] { '|' }); FormsIdentity fi = (FormsIdentity)(Context.User.Identity); Context.User = new System.Security.Principal.GenericPrincipal(fi, roles); }} We ensure that a user has permissions to view a record by creating a custom attribute AuthorizeToViewID that inherits from ActionFilterAttribute. public class AuthorizeToViewIDAttribute : ActionFilterAttribute{ IEmployeeRepository employeeRepository = new EmployeeRepository(); public override void OnActionExecuting(ActionExecutingContext filterContext) { if (filterContext.ActionParameters.ContainsKey("id") && filterContext.ActionParameters["id"] != null) { if (employeeRepository.IsAuthorizedToView((int)filterContext.ActionParameters["id"])) { return; } } throw new UnauthorizedAccessException("The record does not exist or you do not have permission to access it"); }} We add the AuthorizeToView attribute to any Action method that requires authorization. [HttpPost][Authorize(Order = 1)]//To prevent CSRF[ValidateAntiForgeryToken(Salt = Globals.EditSalt, Order = 2)]//See AuthorizeToViewIDAttribute class[AuthorizeToViewID(Order = 3)] [ActionName("Edit")]public ActionResult Update(int id){ var employeeToEdit = employeeRepository.GetEmployee(id); if (employeeToEdit != null) { //Employees can edit only their address //A manager can edit the title and salary of their subordinate string[] whiteList = (employeeToEdit.IsSubordinate) ? new string[] { "Title", "Salary" } : new string[] { "Address" }; if (TryUpdateModel(employeeToEdit, whiteList)) { employeeRepository.Save(employeeToEdit); return RedirectToAction("Details", new { id = id }); } else { ModelState.AddModelError("", "Please correct the following errors."); } } return View(employeeToEdit);} The Authorize attribute is added to ensure that only authorized users can execute that Action. We use the TryUpdateModel with a white list to ensure that (a) an employee is able to edit only their Address and (b) that a manager is able to edit only the Title and Salary of a subordinate. This works in conjunction with the AuthorizeToViewIDAttribute. The ValidateAntiForgeryToken attribute is added (with a salt) to avoid CSRF. The Order on the attributes specify the order in which the attributes are executed. The Edit View uses the AntiForgeryToken helper to render the hidden token: ......<% using (Html.BeginForm()) {%><%=Html.AntiForgeryToken(NorthwindHR.Models.Globals.EditSalt)%><%= Html.ValidationSummary(true, "Please correct the errors and try again.") %><div class="editor-label"> <%= Html.LabelFor(model => model.LastName) %></div><div class="editor-field">...... The application uses View specific models for ease of model binding. public class EmployeeViewModel{ public int EmployeeID; [Required] [DisplayName("Last Name")] public string LastName { get; set; } [Required] [DisplayName("First Name")] public string FirstName { get; set; } [Required] [DisplayName("Title")] public string Title { get; set; } [Required] [DisplayName("Address")] public string Address { get; set; } [Required] [DisplayName("Salary")] [Range(500, double.MaxValue)] public decimal Salary { get; set; } public bool IsSubordinate { get; set; }} To help with displaying readonly/editable fields, we use a helper method. //Simple extension method to display a TextboxFor or DisplayFor based on the isEditable variablepublic static MvcHtmlString TextBoxOrLabelFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, bool isEditable){ if (isEditable) { return htmlHelper.TextBoxFor(expression); } else { return htmlHelper.DisplayFor(expression); }} The helper method is used in the view like so: <%=Html.TextBoxOrLabelFor(model => model.Title, Model.IsSubordinate)%> As mentioned in this post, there is a much easier way to update properties on an object. Download Demo Project VS 2008, ASP.NET MVC 2 RTM Remember to change the connectionString to point to your Northwind DB NorthwindHR.zip Feedback and bugs are always welcome :-)

Search Results

Search found 24245 results on 970 pages for 'date model'.

Page 254/970 | < Previous Page | 250 251 252 253 254 255 256 257 258 259 260 261 | Next Page >

- by rh0dium

- by kumar

- by peku33

- by Lost_in_code

- by john

- by con_9

- by Telkitty

- by kernix

- by John Smith

- by Program.X

- by kuki

- by imran_ku07

- by rajbk

- by Allan Rwakatungu

- by Antony Reynolds

- by user281985

- by David Paquette

- by Pinal Dave

- by Ben Rees

- by skjagini

- by Laurent

- by sissonb

- by user1637491

- by Rick Strahl

- by rajbk

< Previous Page | 250 251 252 253 254 255 256 257 258 259 260 261 | Next Page >