Search Results

Search found 17884 results on 716 pages for 'column types'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 134/716 | < Previous Page | 130 131 132 133 134 135 136 137 138 139 140 141  | Next Page >

  • If I use a facade class with generic methods to access the JPA API, how should I provide additional processing for specific types?

    - by Shaun
    Let's say I'm making a fairly simple web application using JAVA EE specs (I've heard this is possible). In this app, I only have about 10 domain/data objects, and these are represented by JPA Entities. Architecturally, I would consider the JPA API to perform the role of a DAO. Of course, I don't want to use the EntityManager directly in my UI (JSF) and I need to manage transactions, so I delegate these tasks to the so-called service layer. More specifically, I would like to be able to handle these tasks in a single DataService class (often also called CrudService) with generic methods. See this article by Adam Bien for an example interface: http://www.adam-bien.com/roller/abien/entry/generic_crud_service_aka_dao My project differs from that article in that I can't use EJBs, so my service classes are essentially just named beans and I handle transactions manually. Regardless, what I want is a single interface for simple CRUD operations on my data objects because having a different class for each data type would lead to a lot of duplicate and/or unnecessary code. Ideally, my views would be able to use a method such as public <T> List<T> findAll(Class<T> type) { ... } to retrieve data. Using JSF, it might look something like this: <h:dataTable value="#{dataService.findAll(data.class)}" var="d"> ... </h:dataTable> Similarly, after validating forms, my controller could submit the data with a method such as: public <T> void add(T entity) { ... } Granted, you'd probably actually want to return something useful to the caller. In any case, this works well if your data can be treated as homogenous in this manner. Alas, it breaks down when you need to perform additional processing on certain objects before passing them on to JPA. For example, let's say I'm dealing with Books and Authors which have a many-to-many relationship. Each Book has a set of IDs referring to its authors, and each Author has a set of IDs referring to their books. Normally, JPA can manage this kind of relationship for you, but in some cases it can't (for example, the google app engine JPA provider doesn't support this). Thus, when I persist a new book for example, I may need to update the corresponding author entities. My question, then, is if there's an elegant way to handle this or if I should reconsider the sanity of my whole design. Here's a couple ways I see of dealing with it: The instanceof operator. I could use this to target certain classes when special processing is needed. Perhaps maintainability suffers and it isn't beautiful code, but if there's only 10 or so domain objects it can't be all that bad... could it? Make a different service for each entity type (ie, BookService and AuthorService). All services would inherit from a generic DataService base class and override methods if special processing is needed. At this point, you could probably also just call them DAOs instead. As always, I appreciate the help. Let me know if any clarifications are needed, as I left out many smaller details.

    Read the article

  • Splitting values into groups evenly

    - by Paul Knopf
    Let me try to explain the situation the best I can. Lets say I have 3 values 1, 2, 3 I tell an algorithm to split this values into x columns. Lets say x = 2 for clarification. The algorithm determines that the group of values is best put into two columns the following way. 1st column 2nd column --------------------------- 1 3 2 Each column has an even number (totals, not literals) value. Now lets say I have the following values 7, 8, 3, 1, 4 I tell the algorithm that I want the values split into 3 columns. The algorithm now tells me that the following is the best fit. 1st column 2nd column 3rd column 8 7 3 1 4 Notice how the columns arent quiet even, but it is as close as it can get. A little over and a little under is considered ok, as long as the list is AS CLOSE TO EVEN AS IT CAN BE. Anybody got any suggestions? Know any good methods of doing this?

    Read the article

  • Why does this static factory method involving implied generic types, work?

    - by Cheeso
    Consider public class Tuple<T1, T2> { public Tuple(T1 v1, T2 v2) { V1 = v1; V2 = v2; } public T1 V1 { get; set; } public T2 V2 { get; set; } } public static class Tuple { // MAGIC!! public static Tuple<T1, T2> New<T1, T2>(T1 v1, T2 v2) { return new Tuple<T1, T2>(v1, v2); } } Why does the part labeled "MAGIC" in the above work? It allows syntax like Tuple.New(1, "2") instead of new Tuple<int, string>(1, "2"), but ... how and why? Why do I not need Tuple.New<int,string>(1, "2") ??

    Read the article

  • How to identify each parameter type in a C# method?

    - by user465876
    I have a C# method say: MyMethod(int num, string name, Color color, MyComplexType complex) Using reflection, how can I distinctly identify each of the parameter types of any method? I want to perform some task by parameter type. If the type is simple int, string or boolean then I do something, if it is Color, XMLDocument, etc I do something else and if it is user defined type like MyComplexType or MyCalci etc then I want to do certain task. I am able to retrieve all the parameters of a method using ParameterInfo and can loop through each parameter and get their types. But how can I identify each data type? foreach (var parameter in parameters) { //identify primitive types?? //identify value types //identify reference types } Edit: this is apart of my code to create a propert grid sort of page where I want to show the parameter list with data types for the selected method. If the parameter has any userdefined type/reference type then I want to expand it further to show all the elements under it with datatypes.

    Read the article

  • Looking for a full list of jQuery event types.

    - by serg555
    Where I can find a complete list of all jQuery supported events (like click, mouseup etc) with some explanations when they are triggered? I am looking for those that can be binded: $('#foo').bind('click', handler); For example I just found out by accident that there is paste event but I can't find any references to it anywhere in their docs. What else is there?

    Read the article

  • Declaring two classes that contain instance variables of each others' types.

    - by Benji XVI
    Let’s say you wish to have two classes like so, each declaring an instance variable that is of the other’s class. @interface A : NSObject { B *something; } @end @interface B : NSObject { A *something; } @end It seems to be impossible to declare these classes with these instance variables. In order for A to include an IV of class B, B must already be compiled, and so its @interface must come before A’s. But A’s must be put before B’s for the same reason. Putting the two class declarations in separate files, and #import-ing each other’s .h doesn’t work either, for obvious reasons. So, what is the solution? Or is this either (1) impossible or (2) indicative of a bad design anyway?

    Read the article

  • Password Security: Short and Complex versus ‘Short or Lengthy’ and Less Complex

    - by Akemi Iwaya
    Creating secure passwords for our online accounts is a necessary evil due to the huge increase in database and account hacking that occurs these days. The problem though is that no two companies have a similar policy for complex and secure password creation, then factor in the continued creation of insecure passwords or multi-site use of the same password and trouble is just waiting to happen. Ars Technica decided to take a look at multiple password types, how users fared with them, and how well those password types held up to cracking attempts in their latest study. The password types that Ars Technica looked at were comprehensive8, basic8, and basic16. The comprehensive type required a variety of upper-case, lower-case, digits, and symbols with no dictionary words allowed. The only restriction on the two basic types was the number of characters used. Which type do you think was easier for users to adopt and did better in the two password cracking tests? You can learn more about how well users did with the three password types and the results of the tests by visiting the article linked below. What are your thoughts on the matter? Are shorter, more complex passwords better or worse than using short or long, but less complex passwords? What methods do you feel work best since most passwords are limited to approximately 16 characters in length? Perhaps you use a service like LastPass or keep a dedicated list/notebook to manage your passwords. Let us know in the comments!    

    Read the article

  • SQL SERVER – Difference Between DATETIME and DATETIME2

    - by pinaldave
    Yesterday I have written a very quick blog post on SQL SERVER – Difference Between GETDATE and SYSDATETIME and I got tremendous response for the same. I suggest you read that blog post before continuing this blog post today. I had asked people to honestly take part and share their view about above two system function. There are few emails as well few comments on the blog post asking question how did I come to know the difference between the same. The answer is real world issues. I was called in for performance tuning consultancy where I was asked very strange question by one developer. Here is the situation he was facing. System had a single table with two different column of datetime. One column was datelastmodified and second column was datefirstmodified. One of the column was DATETIME and another was DATETIME2. Developer was populating them with SYSDATETIME respectively. He was always thinking that the value inserted in the table will be the same. This table was only accessed by INSERT statement and there was no updates done over it in application.One fine day he ran distinct on both of this column and was in for surprise. He always thought that both of the table will have same data, but in fact they had very different data. He presented this scenario to me. I said this can not be possible but when looked at the resultset, I had to agree with him. Here is the simple script generated to demonstrate the problem he was facing. This is just a sample of original table. DECLARE @Intveral INT SET @Intveral = 10000 CREATE TABLE #TimeTable (FirstDate DATETIME, LastDate DATETIME2) WHILE (@Intveral > 0) BEGIN INSERT #TimeTable (FirstDate, LastDate) VALUES (SYSDATETIME(), SYSDATETIME()) SET @Intveral = @Intveral - 1 END GO SELECT COUNT(DISTINCT FirstDate) D_GETDATE, COUNT(DISTINCT LastDate) D_SYSGETDATE FROM #TimeTable GO SELECT DISTINCT a.FirstDate, b.LastDate FROM #TimeTable a INNER JOIN #TimeTable b ON a.FirstDate = b.LastDate GO SELECT * FROM #TimeTable GO DROP TABLE #TimeTable GO Let us see the resultset. You can clearly see from result that SYSDATETIME() does not populate the same value in the both of the field. In fact the value is either rounded down or rounded up in the field which is DATETIME. Event though we are populating the same value, the values are totally different in both the column resulting the SELF JOIN fail and display different DISTINCT values. The best policy is if you are using DATETIME use GETDATE() and if you are suing DATETIME2 use SYSDATETIME() to populate them with current date and time to accurately address the precision. As DATETIME2 is introduced in SQL Server 2008, above script will only work with SQL SErver 2008 and later versions. I hope I have answered few questions asked yesterday. Reference: Pinal Dave (http://www.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL DateTime, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • Dynamic Unpivot : SSIS Nugget

    - by jamiet
    A question on the SSIS forum earlier today asked: I need to dynamically unpivot some set of columns in my source file. Every month there is one new column and its set of Values. I want to unpivot it without editing my SSIS packages that is deployed Let’s be clear about what we mean by Unpivot. It is a normalisation technique that basically converts columns into rows. By way of example it converts something like this: AccountCode Jan Feb Mar AC1 100.00 150.00 125.00 AC2 45.00 75.50 90.00 into something like this: AccountCode Month Amount AC1 Jan 100.00 AC1 Feb 150.00 AC1 Mar 125.00 AC2 Jan 45.00 AC2 Feb 75.50 AC2 Mar 90.00 The Unpivot transformation in SSIS is perfectly capable of carrying out the operation defined in this example however in the case outlined in the aforementioned forum thread the problem was a little bit different. I interpreted it to mean that the number of columns could change and in that scenario the Unpivot transformation (and indeed the SSIS dataflow in general) is rendered useless because it expects that the number of columns will not change from what is specified at design-time. There is a workaround however. Assuming all of the columns that CAN exist will appear at the end of the rows, we can (1) import all of the columns in the file as just a single column, (2) use a script component to loop over all the values in that “column” and (3) output each one as a column all of its own. Let’s go over that in a bit more detail.   I’ve prepared a data file that shows some data that we want to unpivot which shows some customers and their mythical shopping lists (it has column names in the first row): We use a Flat File Connection Manager to specify the format of our data file to SSIS: and a Flat File Source Adapter to put it into the dataflow (no need a for a screenshot of that one – its very basic). Notice that the values that we want to unpivot all exist in a column called [Groceries]. Now onto the script component where the real work goes on, although the code is pretty simple: Here I show a screenshot of this executing along with some data viewers. As you can see we have successfully pulled out all of the values into a row all of their own thus accomplishing the Dynamic Unpivot that the forum poster was after. If you want to run the demo for yourself then I have uploaded the demo package and source file up to my SkyDrive: http://cid-550f681dad532637.skydrive.live.com/self.aspx/Public/BlogShare/20100529/Dynamic%20Unpivot.zip Simply extract the two files into a folder, make sure the Connection Manager is pointing to the file, and execute! Hope this is useful. @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

    Read the article

  • Customize the Five Windows Folder Templates

    - by Mark Virtue
    Are you’re particular about the way Windows Explorer presents each folder’s contents? Here we show you how to take advantage of Explorer’s built-in templates, which cuts down the time it takes to do customizations. Note: The techniques in this article apply to Windows XP, Vista, and Windows 7. When opening a folder for the first time in Windows Explorer, we are presented with a standard default view of the files and folders in that folder. It may be that the items are presented are perfectly fine, but on the other hand, we may want to customize the view.  The aspects of it that we can customize are the following: The display type (list view, details, tiles, thumbnails, etc) Which columns are displayed, and in which order The widths of the visible columns The order in which the files and folders are sorted Any file groupings Thankfully, Windows offers us a shortcut.  A particular folder’s settings can be used as a “template” for other, similar folders.  In fact, we can store up to five separate sets of folder presentation configurations.  Once we save the settings for a particular template, that template can then be applied to other folders. Customize Your First Folder We’ll start by setting up the first of our templates – the default one.  Once we create this template and apply it, the vast majority of the folders in our file system will change to match it, so it’s important that we set it up very carefully.  The first step in creating and applying the template is to customize one folder with the settings that all the rest will have. Choose a folder that is typical of the folders that you wish to have this default template.  Select it in Windows Explorer.  To ensure that it is a suitable candidate, right-click the folder name and select Properties, then go to the Customize tab.  Ensure that this folder is marked as General Items.  If it is not, either choose a different folder or select General Items from the list. Click OK.  Now we’re ready to customize our first folder. Changing the way one single folder is presented is straightforward.  We start with the folder’s display type.  Click the Change your view button in the top-right corner of every Explorer window. Each time you click the button, the folder’s view cycles to the next view type.  Alternatively you can click the little down-arrow next to the button to see all the display types at once, and select the one you want. Click the view you want, or drag the slider next to the one you want. If you have chosen Details, then the next thing you may wish to change is which columns are displayed, and the order of these.  To choose which columns are displayed, simply right-click on any column heading.  A list of the columns currently being display appears. Simply uncheck a column if you don’t want it displayed, and check the columns that you want displayed.  If you want some information displayed about your files that is not listed here, then click the More… button for a full list of file attributes. There’s a lot of them! To change the order of the columns that are currently being displayed, simply click on a column heading and drag it to where you think it should be.  To change the width of a column, click the line that represents the right-hand edge of the column and drag it left or right. To sort by a column, click once on that column.  To reverse the sort-order, click that same column again. To change the groupings of the files in the folder, right-click in a blank area of the folder, select Group by, and select the appropriate column. Apply This Default Template to All Similar Folders Once you have the folder exactly the way you want it, we now use this folder as our default template for most of the folders in our file system.  To do this, ensure that you are still in the folder you just customized, and then, from the Organize menu in Explorer, click on Folder and search options. Then select the View tab and click the Apply to Folders button. After you’ve clicked OK, visit some of the other folders in your file system.  You should see that most have taken on these new settings. What we’ve just done, in effect, is we have customized the General Items template.  This is one of five templates that Windows Explorer uses to display folder contents.  The five templates are called (in Windows 7): General Items Documents Pictures Music Videos When a folder is opened, Windows Explorer examines the contents to see if it can automatically determine which folder template to use to display the folder contents.  If it is not obvious that the folder contents falls into any of the last four templates, then Windows Explorer chooses the General Items template.  That’s why most of the folders in your file system are shown using the General Items template. Changing the Other Four Templates If you want to adjust the other four templates, the process is very similar to what we’ve just done.  If you wanted to change the “Music” template, for example, the steps would be as follows: Select a folder that contains music items Apply the existing Music template to the folder (even if it doesn’t look like you want it to) Customize the folder to your personal preferences Apply the new template to all “Music” folders A fifth step would be:  When you open a folder that contains music items but is not automatically displayed using the Music template, you manually select the Music template for that folder. First, select a folder that contains music items.  It will probably be displayed using the existing Music template: Next, ensure that it is using the Music template.  If it’s not, then manually select the Music template. Next, customize the folder to suit your personal preferences (here we’ve added a couple of columns, and sorted by Artist). Now we can set this view to be our Music template.  Choose Organize, then the View tab, and click the Apply to Folders button. Note: The only folders that will inherit these settings are the ones that are currently (or will soon be) using the Music template. Now, if you have any folder that contains music items, and you want it to inherit all of these settings, then right-click the folder name, choose Properties, and select that this folder should use the Music template.  You can also cehck the box entitled Also apply this template to all subfolders if you want to save yourself even more time with all the sub-folders. Conclusion It’s neat to be able to set up templates for your folder views like this.  It’s a shame that Microsoft didn’t take the concept just a little further and allow you to create as many templates as you want. Similar Articles Productive Geek Tips Fix For When Windows Explorer in Vista Stops Showing File NamesCustomize the Windows 7 or Vista Send To MenuFix for New Contact Group Button Not Displaying in VistaWhy Did Windows Vista’s Music Folder Icon Turn Yellow?Make Your Last Minute Holiday Cards with Microsoft Word TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Office 2010 reviewed in depth by Ed Bott FoxClocks adds World Times in your Statusbar (Firefox) Have Fun Editing Photo Editing with Citrify Outlook Connector Upgrade Error Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7

    Read the article

  • Adding an expression based image in a client report definition file (RDLC)

    - by rajbk
    In previous posts, I showed you how to create a report using Visual Studio 2010 and how to add a hyperlink to the report.  In this post, I show you how to add an expression based image to each row of the report. This similar to displaying a checkbox column for Boolean values.  A sample project is attached to the bottom of this post. To start off, download the project we created earlier from here.  The report we created had a “Discontinued” column of type Boolean. We are going to change it to display an “available” icon or “unavailable” icon based on the “Discontinued” row value.    Load the project and double click on Products.rdlc. With the report design surface active, you will see the “Report Data” tool window. Right click on the Images folder and select “Add Image..”   Add the available_icon.png and discontinued_icon.png images (the sample project at the end of this post has the icon png files)    You can see the images we added in the “Report Data” tool window.   Drag and drop the available_icon into the “Discontinued” column row (not the header) We get a dialog box which allows us to set the image properties. We will add an expression that specifies the image to display based the “Discontinued” value from the Product table. Click on the expression (fx) button.   Add the following expression : = IIf(Fields!Discontinued.Value = True, “discontinued_icon”, “available_icon”)   Save and exit all dialog boxes. In the report design surface, resize the column header and change the text from “Discontinued” to “In Production”.   (Optional) Right click on the image cell (not header) , go to “Image Properties..” and offset it by 5pt from the left. (Optional) Change the border color since it is not set by default for image columns. We are done adding our image column! Compile the application and run it. You will see that the “In Production” column has red ‘x’ icons for discontinued products. Download the VS 2010 sample project NorthwindReportsImage.zip Other Posts Adding a hyperlink in a client report definition file (RDLC) Rendering an RDLC directly to the Response stream in ASP.NET MVC ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager Localization in ASP.NET MVC 2 using ModelMetadata Setting up Visual Studio 2010 to step into Microsoft .NET Source Code Running ASP.NET Webforms and ASP.NET MVC side by side Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework

    Read the article

  • SQL SERVER – Online Index Rebuilding Index Improvement in SQL Server 2012

    - by pinaldave
    Have you ever faced situation when you see something working and you feel it should not be working? Well, I had similar moments few days ago. I know that SQL Server 2008 supports online indexing. However, I also know that I cannot rebuild index ONLINE if I have used VARCHAR(MAX), NVARCHAR(MAX) or few other data types. While I held my belief very strongly I came across situation, where I had to go online and do little bit reading from Book Online. Here is the similar example. First of all – run following code in SQL Server 2008 or SQL Server 2008 R2. USE TempDB GO CREATE TABLE TestTable (ID INT, FirstCol NVARCHAR(10), SecondCol NVARCHAR(MAX)) GO CREATE CLUSTERED INDEX [IX_TestTable] ON TestTable (ID) GO CREATE NONCLUSTERED INDEX [IX_TestTable_Cols] ON TestTable (FirstCol) INCLUDE (SecondCol) GO USE [tempdb] GO ALTER INDEX [IX_TestTable_Cols] ON [dbo].[TestTable] REBUILD WITH (ONLINE = ON) GO DROP TABLE TestTable GO Now run the same code in SQL Server 2012 version. Observe the difference between both of the execution. You will be get following resultset. In SQL Server 2008/R2 it will throw following error: Msg 2725, Level 16, State 2, Line 1 An online operation cannot be performed for index ‘IX_TestTable_Cols’ because the index contains column ‘SecondCol’ of data type text, ntext, image, varchar(max), nvarchar(max), varbinary(max), xml, or large CLR type. For a non-clustered index, the column could be an include column of the index. For a clustered index, the column could be any column of the table. If DROP_EXISTING is used, the column could be part of a new or old index. The operation must be performed offline. In SQL Server 2012 it will run successfully and will not throw any error. Command(s) completed successfully. I always thought it will throw an error if there is VARCHAR(MAX) or NVARCHAR(MAX) used in table schema definition. When I saw this result it was clear to me that it will be for sure not bug enhancement in SQL Server 2012. For matter for the fact, I always wanted this feature to be added in SQL Server Engine as this will enable ONLINE Index Rebuilding for mission critical tables which needs to be always online. I quickly searched online and landed on Jacob Sebastian’s blog where he has blogged about it as well. Well, is there any other new feature in SQL Server 2012 which gave you good surprise? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • Incremental Statistics Maintenance – what statistics will be gathered after DML occurs on the table?

    - by Maria Colgan
    Incremental statistics maintenance was introduced in Oracle Database 11g to improve the performance of gathering statistics on large partitioned table. When incremental statistics maintenance is enabled for a partitioned table, oracle accurately generated global level  statistics by aggregating partition level statistics. As more people begin to adopt this functionality we have gotten more questions around how they expected incremental statistics to behave in a given scenario. For example, last week we got a question around what partitions should have statistics gathered on them after DML has occurred on the table? The person who asked the question assumed that statistics would only be gathered on partitions that had stale statistics (10% of the rows in the partition had changed). However, what they actually saw when they did a DBMS_STATS.GATHER_TABLE_STATS was all of the partitions that had been affected by the DML had statistics re-gathered on them. This is the expected behavior, incremental statistics maintenance is suppose to yield the same statistics as gathering table statistics from scratch, just faster. This means incremental statistics maintenance needs to gather statistics on any partition that will change the global or table level statistics. For instance, the min or max value for a column could change after just one row is inserted or updated in the table. It might easier to demonstrate this using an example. Let’s take the ORDERS2 table, which is partitioned by month on order_date.  We will begin by enabling incremental statistics for the table and gathering statistics on the table. After the statistics gather the last_analyzed date for the table and all of the partitions now show 13-Mar-12. And we now have the following column statistics for the ORDERS2 table. We can also confirm that we really did use incremental statistics by querying the dictionary table sys.HIST_HEAD$, which should have an entry for each column in the ORDERS2 table. So, now that we have established a good baseline, let’s move on to the DML. Information is loaded into the latest partition of the ORDERS2 table once a month. Existing orders maybe also be update to reflect changes in their status. Let’s assume the following transactions take place on the ORDERS2 table this month. After these transactions have occurred we need to re-gather statistic since the partition ORDERS_MAR_2012 now has rows in it and the number of distinct values and the maximum value for the STATUS column have also changed. Now if we look at the last_analyzed date for the table and the partitions, we will see that the global statistics and the statistics on the partitions where rows have changed due to the update (ORDERS_FEB_2012) and the data load (ORDERS_MAR_2012) have been updated. The column statistics also reflect the changes with the number of distinct values in the status column increase to reflect the update. So, incremental statistics maintenance will gather statistics on any partition, whose data has changed and that change will impact the global level statistics.

    Read the article

  • How-to filter table filter input to only allow numeric input

    - by frank.nimphius
    In a previous ADF Code Corner post, I explained how to change the table filter behavior by intercepting the query condition in a query filter. See sample #30 at http://www.oracle.com/technetwork/developer-tools/adf/learnmore/index-101235.html In this OTN Harvest post I explain how to prevent users from providing invalid character entries as table filter criteria to avoid problems upon re-querying the table. In the example shown next, only numeric values are allowed for a table column filter. To create a table that allows data filtering, drag a View Object – or a data collection of a Web Service or JPA business service – from the DataControls panel and drop it as a table. Choose the Enable Filtering option in the Edit Table Columns dialog so the table renders with the column filter boxes displayed. The table filter fields are created using implicit af:inputText components that need to be customized for you to apply a custom filter input component, or to change the input behavior. To change the input filter, so only a defined set of input keys is allowed, you need to change the default filter field with your own af:inputText field to which you apply an af:clientListener tag that filters user keyboard entries. For this, in the Oracle JDeveloper visual editor, select the column which filter you want to change and expand the column node in the Oracle JDeveloper Structure Window. Part of the column definition is the Column facet node. Expand the facets so you see the filter facet entry. The filter facet is grayed out as there is no custom facet defined. In a next step, open theComponent Palette (ctrl+shift+P) and drag an Input Text component onto the facet. This demarks the first part in the filter customization. To make the custom filter component work, you need to map the af:inputText component value property to the ADF filter criteria that is exposed in the Expression Builder. Open the Expression Builder for the filter input component value property by clicking the arrow icon to its right. In the Expression Builder expand the JSP Objects | vs | filterCriteria node to select the attribute name represented by the table column. The vs entry is the name of a variable that is defined on the table and that grants you access to the table attributes. Now that the filter works as before – though using a custom filter input component – you can add the af:clientListener tag to your custom filter component – af:inputText – to call out to JavaScript when users type in the column filter field Point the client filter method property to a JavaScript function that you reference or add through using the af:resource tag and set the type property value to keyDown. <af:document id="d1">     <af:resource type="javascript" source="/js/filterHandler.js"/> … The filter definition looks as shown below <af:inputText label="Label 1" id="it1"                         value="#{vs.filterCriteria.Employe        <af:clientListener method="suppressCharacterInput"                                     type="keyDown"/> </af:inputText> The JavaScript code that you can use to either filter character inputs or numeric inputs is shown below. Just store this code in an external JavaScript (.js) file and reference it from the af:resource tag. //Allow numbers, cursor control keys and delete keys function suppressCharacterInput(evt) {     var _keyCode = evt.getKeyCode();     var _filterField = evt.getCurrentTarget();     var _oldValue = _filterField.getValue();     if (!((_keyCode < 57) ||(_keyCode > 96 && _keyCode < 105))) {         _filterField.setValue(_oldValue);         evt.cancel();     } } //Allow characters, cursor control keys and delete keys function suppressNumericInput(evt) {  var _keyCode = evt.getKeyCode();  var _filterField = evt.getCurrentTarget();  var _oldValue = _filterField.getValue();  //check for numbers  if ((_keyCode < 57 && _keyCode > 47) ||      (_keyCode > 96 && _keyCode < 105)){     _filterField.setValue(_oldValue);     evt.cancel();   } } But what if browsers don't allow JavaScript ? Don't worry about this. If browsers would not support JavaScript then ADF Faces as a whole would not work and you had a different problem.

    Read the article

  • July, the 31 Days of SQL Server DMO’s – Day 20 (sys.dm_tran_locks)

    - by Tamarick Hill
    The sys.dm_tran_locks DMV is used to return active lock resources on your server. Locking is a mechanism used by SQL Server to protect the integrity of data when you have multiple users that may potentially access the same data at the same time. Let’s run a query against this DMV so we can analyze the results. SELECT * FROM sys.dm_tran_locks As we can see, its a lot of lock information returned from this DMV. I will not go into detail about each of the columns returned, but I will touch on the ones that I feel are the most important. The first column in the output is the resource_type column which tells you the type of lock a particular row represents. It could be a PAGE lock, RID, OBJECT, DATABASE, or several other lock types. The resource_database_id represents the id of the database for a particular lock resource. The resource_lock_partition column represents the ID of a lock partition. When you have a table that is partitioned, locks can be escalated to the partition level before going to a table level lock. The request_mode column gives us information about the type of lock that is being requested. From the screenshots above we see RangeS-S locks which represent a share range lock and IS locks which represent Intent Shared locks. The request_status column displays whether the lock has been granted or whether the lock is waiting to be acquired. The request_session_id  shows the session_id that is requesting the lock. This DMV is the best place to go when you need to identify the exact locks that are being held or pending for individual requests. You might need this information when you are troubleshooting severe blocking or deadlocking problems on your server. For more information on this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms190345.aspx Follow me on Twitter @PrimeTimeDBA

    Read the article

  • Plan your SharePoint 2010 Content Type Hub carefully

    - by Wayne
    Currently setting up a new environment on SharePoint 2010 (which was made available for download yesterday if anyone missed that :-). One of the new features of SharePoint 2010 is to set up a Content Type Hub (which is a part of the Metadata Service Application), which is a hub for all Content Types that other Site Collections can subscribe to. That is you only need to manage your content types in one location. Setting up the Content Type Hub is not that difficult but you must make it very careful to avoid a lot of work and troubleshooting. Here is a short tutorial with a few tips and tricks to make it easy for you to get started. Determine location of Content Type Hub First of all you need to decide in which Site Collection to place your Content Type Hub; in the root site collection or a specific one. I think using a specific Site Collection that only acts as a Content Type Hub is the best way, there are no best practice as of now. So I create a new Site Collection, at for instance http://server/sites/CTH/. The top-level site of this site collection should be for instance a Team Site. You cannot use Blank Site by default, which would have been the best option IMHO, since that site does not have the Taxonomy feature stapled upon it (check the TaxonomyFeatureStapler feature for which site templates that can be used). Configure Managed Metadata Service Application Next you need to create your Managed Metadata Service Application or configure the existing one, Central Administration > Application Management > Manage Service Applications. Select the Managed Metadata service application and click Properties if you already have created it. In the bottom of the dialog window when you are creating the service application or when you are editing the properties is a section to fill in the Content Type Hub. In this text box fill in the URL of the Content Type Hub. It is essential that you have decided where your Content Type Hub will reside, since once this is set you cannot change it. The only way to change it is to rebuild the whole managed metadata service application! Also make sure that you enter the URL correctly. I did copy and paste the URL once and got the /default.aspx in the URL which funked the whole service up. Make sure that you only use the URL to the Site Collection of the hub. Now you have to set up so that other Site Collections can consume the content types from the hub. This is done by selecting the connection for the managed metadata service application and clicking properties. A new dialog window opens and there you need to click the Consumes content types from the Content Type Gallery at nnnn. Now you are free to syndicate your Content Types from the Hub. Publish Content Types To publish a Content Type from the hub you need to go to Site Settings > Content Types and select the content type that you would like to publish. Then select Manage publishing for this content type. This takes you to a page from where you can Publish, Unpublish or Republish the content type. Once the content type is published it can take up to an hour for the subscribing Site Collections to get it. This is controlled by the Content Type Subscriber job that is scheduled to run once an hour. To speed up your publishing just go to Central Administration > Monitoring > Review Job Definitions > Content Type Subscriber and click Run now and you content type is very soon available for use. Published Content Type status You can check the status of the content type publishing in your destination site collections by selecting Site Settings > Content Type Publishing. From here you can force a refresh of all subscribed content types, see which ones that are subscribed and finally check the publishing error log. This error log is very useful for detecting errors during the publishing. For instance if you use any features such as ratings, metadata, document ids in your content type hub and your destination site collection does not have those features available this will be reported here.

    Read the article

  • Date and Time Support in SQL Server 2008

    - by Aamir Hasan
      Using the New Date and Time Data Types Normal 0 false false false EN-US X-NONE X-NONE /* 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;} 1.       The new date and time data types in SQL Server 2008 offer increased range and precision and are ANSI SQL compatible. 2.       Separate date and time data types minimize storage space requirements for applications that need only date or time information. Moreover, the variable precision of the new time data type increases storage savings in exchange for reduced accuracy. 3.       The new data types are mostly compatible with the original date and time data types and use the same Transact-SQL functions. 4.       The datetimeoffset data type allows you to handle date and time information in global applications that use data that originates from different time zones. SELECT c.name, p.* FROM politics pJOIN country cON p.country = c.codeWHERE YEAR(Independence) < 1753ORDER BY IndependenceGO8.    Highlight the SELECT statement and click Execute ( ) to show the use of some of the date functions.T-SQLSELECT c.name AS [Country Name],        CONVERT(VARCHAR(12), p.Independence, 107) AS [Independence Date],       DATEDIFF(YEAR, p.Independence, GETDATE()) AS [Years Independent (appox)],       p.GovernmentFROM politics pJOIN country cON p.country = c.codeWHERE YEAR(Independence) < 1753ORDER BY IndependenceGO10.    Select the SET DATEFORMAT statement and click Execute ( ) to change the DATEFORMAT to day-month-year.T-SQLSET DATEFORMAT dmyGO11.    Select the DECLARE and SELECT statements and click Execute ( ) to show how the datetime and datetime2 data types interpret a date literal.T-SQLSET DATEFORMAT dmyDECLARE @dt datetime = '2008-12-05'DECLARE @dt2 datetime2 = '2008-12-05'SELECT MONTH(@dt) AS [Month-Datetime], DAY(@dt)     AS [Day-Datetime]SELECT MONTH(@dt2) AS [Month-Datetime2], DAY(@dt2)     AS [Day-Datetime2]GO12.    Highlight the DECLARE and SELECT statements and click Execute ( ) to use integer arithmetic on a datetime variable.T-SQLDECLARE @dt datetime = '2008-12-05'SELECT @dt + 1GO13.    Highlight the DECLARE and SELECT statements and click Execute ( ) to show how integer arithmetic is not allowed for datetime2 variables.T-SQLDECLARE @dt2 datetime = '2008-12-05'SELECT @dt2 + 1GO14.    Highlight the DECLARE and SELECT statements and click Execute ( ) to show how to use DATE functions to do simple arithmetic on datetime2 variables.T-SQLDECLARE @dt2 datetime2(7) = '2008-12-05'SELECT DATEADD(d, 1, @dt2)GO15.    Highlight the DECLARE and SELECT statements and click Execute ( ) to show how the GETDATE function can be used with both datetime and datetime2 data types.T-SQLDECLARE @dt datetime = GETDATE();DECLARE @dt2 datetime2(7) = GETDATE();SELECT @dt AS [GetDate-DateTime], @dt2 AS [GetDate-DateTime2]GO16.    Draw attention to the values returned for both columns and how they are equal.17.    Highlight the DECLARE and SELECT statements and click Execute ( ) to show how the SYSDATETIME function can be used with both datetime and datetime2 data types.T-SQLDECLARE @dt datetime = SYSDATETIME();DECLARE @dt2 datetime2(7) = SYSDATETIME();SELECT @dt AS [Sysdatetime-DateTime], @dt2     AS [Sysdatetime-DateTime2]GO18.    Draw attention to the values returned for both columns and how they are different.Programming Global Applications with DateTimeOffset 2.    If you have not previously created the SQLTrainingKitDB database while completing another demo in this training kit, highlight the CREATE DATABASE statement and click Execute ( ) to do so now.T-SQLCREATE DATABASE SQLTrainingKitDBGO3.    Select the USE and CREATE TABLE statements and click Execute ( ) to create table datetest in the SQLTrainingKitDB database.T-SQLUSE SQLTrainingKitDBGOCREATE TABLE datetest (  id integer IDENTITY PRIMARY KEY,  datetimecol datetimeoffset,  EnteredTZ varchar(40)); Reference:http://www.microsoft.com/downloads/details.aspx?FamilyID=E9C68E1B-1E0E-4299-B498-6AB3CA72A6D7&displaylang=en   

    Read the article

  • Extending QuickBooks Reporting with the QuickBooks ADO.NET Data Provider

    - by dataintegration
    The ADO.NET Provider for QuickBooks comes with several reports you may request from QuickBooks by default. However, there are many more that are not readily available. The ADO.NET Provider for QuickBooks makes it easy for you to create new reports and customize existing ones. In this article, we will illustrate how to create your own report and retrieve it from the Server Explorer in Visual Studio. For this example we will show how to create an Item Profitability Report. Creating the report script file Step 1: Download the sample reports available here. Extract them to a folder of your choice. Step 2: Make a copy of the ReportGeneralSummary.rsd file and rename it to ItemProfitability.rsd. Then open the file in any text editor. Step 3: Open the installation directory of the ADO.NET Provider for QuickBooks. Under the \db\ folder, locate the ReportJob.rsb file. Open this file in another text editor. Note: Although we are using ReportJob.rsb for this example, other reports may be contained in other Report*.rsb files. We recommend consulting the included help file and first locating the Report stored procedure and ReportType you are looking for. Otherwise, you may open each Report*.rsb file and look under the "reporttype" input for the report you are attempting to create. Step 4: First, let's rename the title of ItemProfitability.rsd. Near the top of the file you will see a title and description. Change the title to match the name of the file. Change the description to anything you like. For example: <rsb:info title="ItemProfitability" description="Executes my custom report."> Just below the Title, there are a number of columns. The Id represents the row number. The RowType represents the type of data returned by QuickBooks. The ColumnValue* columns represent all of the column data returned by QuickBooks. In some instances, we may need to add additional ColumnValue columns. Step 5: To add additional ColumnValue columns, simply copy the last column, paste it directly below, and continue increasing the numerical value at end of the attribute name. For example: <attr name="ColumnValue9" xs:type="string" readonly="true" required="false" desc="Represents a column of data."/> <attr name="ColumnValue10" xs:type="string" readonly="true" required="false" desc="Represents a column of data."/> <attr name="ColumnValue11" xs:type="string" readonly="true" required="false" desc="Represents a column of data."/> <attr name="ColumnValue12" xs:type="string" readonly="true" required="false" desc="Represents a column of data."/> ... Caution: Do not rename the ColumnValue* definitions themselves. They are generalized so that we can understand each type of report returned by QuickBooks. Renaming them to something other than ColumnValue* will cause your columns to return with null values. Step 6: Now let's update the available inputs for the table. From the ReportJob.rsb file, copy all of the input elements into ItemProfitability under the "Psuedo-Column definitions" comment. You will be replacing the existing input elements in ItemProfitability with inputs from ReportJob. When you are done, it should look like this: <!-- Psuedo-Column definitions --> <input name="reporttype" description="The type of the report." value="ITEMESTIMATESVSACTUALS,ITEMPROFITABILITY,JOBESTIMATESVSACTUALSDETAIL,JOBESTIMATESVSACTUALSSUMMARY,JOBPROFITABILITYDETAIL,JOBPROFITABILITYSUMMARY," default="ITEMESTIMATESVSACTUALS" /> <input name="reportperiod" description="Report date range in the format (fromdate:todate), and either value may be omitted for an open ended range (e.g. 2009-12-25:). Supported date format: yyyy-MM-dd." /> <input name="reportdaterangemacro" description="Use a predefined date range." value="ALL,TODAY,THISWEEK,THISWEEKTODATE,THISMONTH,THISMONTHTODATE,THISQUARTER,THISQUARTERTODATE,THISYEAR,THISYEARTODATE,YESTERDAY,LASTWEEK,LASTWEEKTODATE,LASTMONTH,LASTMONTHTODATE,LASTQUARTER,LASTQUARTERTODATE,LASTYEAR,LASTYEARTODATE,NEXTWEEK,NEXTFOURWEEKS,NEXTMONTH,NEXTQUARTER,NEXTYEAR," default="ALL" /> ... Step 7: Now let's update the operationname attribute. This needs to match the same operationname used by ReportJob. After you have copied the correct value from ReportJob.rsb, the operationname in ItemProfitability should look like so: <rsb:set attr="operationname" value="qbReportJob"/> Step 8: There is one more thing we can do to make this a true Item Profitability report. We can remove the reporttype input and hardcode the value. To do this, copy and paste the rsb:set used for operationname. Then rename the attr and value to match the name and value you want to use. For example: <rsb:set attr="operationname" value="qbReportJob"/> <rsb:set attr="reporttype" value="ITEMPROFITABILITY"/> After this you can remove the input for reporttype. Now that you have your own report file, we can move on to displaying the report in the Visual Studio server explorer. Accessing the report through the Data Provider Step 1: Open Visual Studio. In the Server Explorer, configure a new connection with the QuickBooks Data Provider. Step 2: For the Location connection string property, enter the directory where the new report has been saved to. Step 3: The new report should appear as a new view in the Server Explorer. Let's retrieve data from it. Step 4: You can specify any inputs in the WHERE clause. New Report Example Script To help you get started using this new QuickBooks Data Provider report, you will need to download the QuickBooks ADO.NET Data Provider and the fully functional sample script.

    Read the article

  • C#/.NET Little Wonders: Fun With Enum Methods

    - by James Michael Hare
    Once again lets dive into the Little Wonders of .NET, those small things in the .NET languages and BCL classes that make development easier by increasing readability, maintainability, and/or performance. So probably every one of us has used an enumerated type at one time or another in a C# program.  The enumerated types we create are a great way to represent that a value can be one of a set of discrete values (or a combination of those values in the case of bit flags). But the power of enum types go far beyond simple assignment and comparison, there are many methods in the Enum class (that all enum types “inherit” from) that can give you even more power when dealing with them. IsDefined() – check if a given value exists in the enum Are you reading a value for an enum from a data source, but are unsure if it is actually a valid value or not?  Casting won’t tell you this, and Parse() isn’t guaranteed to balk either if you give it an int or a combination of flags.  So what can we do? Let’s assume we have a small enum like this for result codes we want to return back from our business logic layer: 1: public enum ResultCode 2: { 3: Success, 4: Warning, 5: Error 6: } In this enum, Success will be zero (unless given another value explicitly), Warning will be one, and Error will be two. So what happens if we have code like this where perhaps we’re getting the result code from another data source (could be database, could be web service, etc)? 1: public ResultCode PerformAction() 2: { 3: // set up and call some method that returns an int. 4: int result = ResultCodeFromDataSource(); 5:  6: // this will suceed even if result is < 0 or > 2. 7: return (ResultCode) result; 8: } So what happens if result is –1 or 4?  Well, the cast does not fail, so what we end up with would be an instance of a ResultCode that would have a value that’s outside of the bounds of the enum constants we defined. This means if you had a block of code like: 1: switch (result) 2: { 3: case ResultType.Success: 4: // do success stuff 5: break; 6:  7: case ResultType.Warning: 8: // do warning stuff 9: break; 10:  11: case ResultType.Error: 12: // do error stuff 13: break; 14: } That you would hit none of these blocks (which is a good argument for always having a default in a switch by the way). So what can you do?  Well, there is a handy static method called IsDefined() on the Enum class which will tell you if an enum value is defined.  1: public ResultCode PerformAction() 2: { 3: int result = ResultCodeFromDataSource(); 4:  5: if (!Enum.IsDefined(typeof(ResultCode), result)) 6: { 7: throw new InvalidOperationException("Enum out of range."); 8: } 9:  10: return (ResultCode) result; 11: } In fact, this is often recommended after you Parse() or cast a value to an enum as there are ways for values to get past these methods that may not be defined. If you don’t like the syntax of passing in the type of the enum, you could clean it up a bit by creating an extension method instead that would allow you to call IsDefined() off any isntance of the enum: 1: public static class EnumExtensions 2: { 3: // helper method that tells you if an enum value is defined for it's enumeration 4: public static bool IsDefined(this Enum value) 5: { 6: return Enum.IsDefined(value.GetType(), value); 7: } 8: }   HasFlag() – an easier way to see if a bit (or bits) are set Most of us who came from the land of C programming have had to deal extensively with bit flags many times in our lives.  As such, using bit flags may be almost second nature (for a quick refresher on bit flags in enum types see one of my old posts here). However, in higher-level languages like C#, the need to manipulate individual bit flags is somewhat diminished, and the code to check for bit flag enum values may be obvious to an advanced developer but cryptic to a novice developer. For example, let’s say you have an enum for a messaging platform that contains bit flags: 1: // usually, we pluralize flags enum type names 2: [Flags] 3: public enum MessagingOptions 4: { 5: None = 0, 6: Buffered = 0x01, 7: Persistent = 0x02, 8: Durable = 0x04, 9: Broadcast = 0x08 10: } We can combine these bit flags using the bitwise OR operator (the ‘|’ pipe character): 1: // combine bit flags using 2: var myMessenger = new Messenger(MessagingOptions.Buffered | MessagingOptions.Broadcast); Now, if we wanted to check the flags, we’d have to test then using the bit-wise AND operator (the ‘&’ character): 1: if ((options & MessagingOptions.Buffered) == MessagingOptions.Buffered) 2: { 3: // do code to set up buffering... 4: // ... 5: } While the ‘|’ for combining flags is easy enough to read for advanced developers, the ‘&’ test tends to be easy for novice developers to get wrong.  First of all you have to AND the flag combination with the value, and then typically you should test against the flag combination itself (and not just for a non-zero)!  This is because the flag combination you are testing with may combine multiple bits, in which case if only one bit is set, the result will be non-zero but not necessarily all desired bits! Thanks goodness in .NET 4.0 they gave us the HasFlag() method.  This method can be called from an enum instance to test to see if a flag is set, and best of all you can avoid writing the bit wise logic yourself.  Not to mention it will be more readable to a novice developer as well: 1: if (options.HasFlag(MessagingOptions.Buffered)) 2: { 3: // do code to set up buffering... 4: // ... 5: } It is much more concise and unambiguous, thus increasing your maintainability and readability. It would be nice to have a corresponding SetFlag() method, but unfortunately generic types don’t allow you to specialize on Enum, which makes it a bit more difficult.  It can be done but you have to do some conversions to numeric and then back to the enum which makes it less of a payoff than having the HasFlag() method.  But if you want to create it for symmetry, it would look something like this: 1: public static T SetFlag<T>(this Enum value, T flags) 2: { 3: if (!value.GetType().IsEquivalentTo(typeof(T))) 4: { 5: throw new ArgumentException("Enum value and flags types don't match."); 6: } 7:  8: // yes this is ugly, but unfortunately we need to use an intermediate boxing cast 9: return (T)Enum.ToObject(typeof (T), Convert.ToUInt64(value) | Convert.ToUInt64(flags)); 10: } Note that since the enum types are value types, we need to assign the result to something (much like string.Trim()).  Also, you could chain several SetFlag() operations together or create one that takes a variable arg list if desired. Parse() and ToString() – transitioning from string to enum and back Sometimes, you may want to be able to parse an enum from a string or convert it to a string - Enum has methods built in to let you do this.  Now, many may already know this, but may not appreciate how much power are in these two methods. For example, if you want to parse a string as an enum, it’s easy and works just like you’d expect from the numeric types: 1: string optionsString = "Persistent"; 2:  3: // can use Enum.Parse, which throws if finds something it doesn't like... 4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result == MessagingOptions.Persistent) 7: { 8: Console.WriteLine("It worked!"); 9: } Note that Enum.Parse() will throw if it finds a value it doesn’t like.  But the values it likes are fairly flexible!  You can pass in a single value, or a comma separated list of values for flags and it will parse them all and set all bits: 1: // for string values, can have one, or comma separated. 2: string optionsString = "Persistent, Buffered"; 3:  4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked!"); 9: } Or you can parse in a string containing a number that represents a single value or combination of values to set: 1: // 3 is the combination of Buffered (0x01) and Persistent (0x02) 2: var optionsString = "3"; 3:  4: var result = (MessagingOptions) Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked again!"); 9: } And, if you really aren’t sure if the parse will work, and don’t want to handle an exception, you can use TryParse() instead: 1: string optionsString = "Persistent, Buffered"; 2: MessagingOptions result; 3:  4: // try parse returns true if successful, and takes an out parm for the result 5: if (Enum.TryParse(optionsString, out result)) 6: { 7: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 8: { 9: Console.WriteLine("It worked!"); 10: } 11: } So we covered parsing a string to an enum, what about reversing that and converting an enum to a string?  The ToString() method is the obvious and most basic choice for most of us, but did you know you can pass a format string for enum types that dictate how they are written as a string?: 1: MessagingOptions value = MessagingOptions.Buffered | MessagingOptions.Persistent; 2:  3: // general format, which is the default, 4: Console.WriteLine("Default : " + value); 5: Console.WriteLine("G (default): " + value.ToString("G")); 6:  7: // Flags format, even if type does not have Flags attribute. 8: Console.WriteLine("F (flags) : " + value.ToString("F")); 9:  10: // integer format, value as number. 11: Console.WriteLine("D (num) : " + value.ToString("D")); 12:  13: // hex format, value as hex 14: Console.WriteLine("X (hex) : " + value.ToString("X")); Which displays: 1: Default : Buffered, Persistent 2: G (default): Buffered, Persistent 3: F (flags) : Buffered, Persistent 4: D (num) : 3 5: X (hex) : 00000003 Now, you may not really see a difference here between G and F because I used a [Flags] enum, the difference is that the “F” option treats the enum as if it were flags even if the [Flags] attribute is not present.  Let’s take a non-flags enum like the ResultCode used earlier: 1: // yes, we can do this even if it is not [Flags] enum. 2: ResultCode value = ResultCode.Warning | ResultCode.Error; And if we run that through the same formats again we get: 1: Default : 3 2: G (default): 3 3: F (flags) : Warning, Error 4: D (num) : 3 5: X (hex) : 00000003 Notice that since we had multiple values combined, but it was not a [Flags] marked enum, the G and default format gave us a number instead of a value name.  This is because the value was not a valid single-value constant of the enum.  However, using the F flags format string, it broke out the value into its component flags even though it wasn’t marked [Flags]. So, if you want to get an enum to display appropriately for whether or not it has the [Flags] attribute, use G which is the default.  If you always want it to attempt to break down the flags, use F.  For numeric output, obviously D or  X are the best choice depending on whether you want decimal or hex. Summary Hopefully, you learned a couple of new tricks with using the Enum class today!  I’ll add more little wonders as I think of them and thanks for all the invaluable input!   Technorati Tags: C#,.NET,Little Wonders,Enum,BlackRabbitCoder

    Read the article

  • The case of the phantom ADF developer (and other yarns)

    - by Chris Muir
    A few years of ADF experience means I see common mistakes made by different developers, some I regularly make myself.  This post is designed to assist beginners to Oracle JDeveloper Application Development Framework (ADF) avoid a common ADF pitfall, the case of the phantom ADF developer [add Scooby-Doo music here]. ADF Business Components - triggers, default table values and instead of views. Oracle's JDeveloper tutorials help with the A-B-Cs of ADF development, typically built on the nice 'n safe demo schema provided by with the Oracle database such as the HR demo schema. However it's not too long until ADF beginners, having built up some confidence from learning with the tutorials and vanilla demo schemas, start building ADF Business Components based upon their own existing database schema objects.  This is where unexpected problems can sneak in. The crime Developers may encounter a surprising error at runtime when editing a record they just created or updated and committed to the database, based on their own existing tables, namely the error: JBO-25014: Another user has changed the row with primary key oracle.jbo.Key[x] ...where X is the primary key value of the row at hand.  In a production environment with multiple users this error may be legit, one of the other users has updated the row since you queried it.  Yet in a development environment this error is just plain confusing.  If developers are isolated in their own database, creating and editing records they know other users can't possibly be working with, or all the other developers have gone home for the day, how is this error possible? There are no other users?  It must be the phantom ADF developer! [insert dramatic music here] The following picture is what you'll see in the Business Component Browser, and you'll receive a similar error message via an ADF Faces page: A false conclusion What can possibly cause this issue if it isn't our phantom ADF developer?  Doesn't ADF BC implement record locking, locking database records when the row is modified in the ADF middle-tier by a user?  How can our phantom ADF developer even take out a lock if this is the case?  Maybe ADF has a bug, maybe ADF isn't implementing record locking at all?  Shouldn't we see the error "JBO-26030: Failed to lock the record, another user holds the lock" as we attempt to modify the record, why do we see JBO-25014? : Let's verify that ADF is in fact issuing the correct SQL LOCK-FOR-UPDATE statement to the database. First we need to verify ADF's locking strategy.  It is determined by the Application Module's jbo.locking.mode property.  The default (as of JDev 11.1.1.4.0 if memory serves me correct) and recommended value is optimistic, and the other valid value is pessimistic. Next we need a mechanism to check that ADF is issuing the LOCK statements to the database.  We could ask DBAs to monitor locks with OEM, but optimally we'd rather not involve overworked DBAs in this process, so instead we can use the ADF runtime setting –Djbo.debugoutput=console.  At runtime this options turns on instrumentation within the ADF BC layer, which among a lot of extra detail displayed in the log window, will show the actual SQL statement issued to the database, including the LOCK statement we're looking to confirm. Setting our locking mode to pessimistic, opening the Business Components Browser of a JSF page allowing us to edit a record, say the CHARGEABLE field within a BOOKINGS record where BOOKING_NO = 1206, upon editing the record see among others the following log entries: [421] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[422] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[423] Where binding param 1: 1206  As can be seen on line 422, in fact a LOCK-FOR-UPDATE is indeed issued to the database.  Later when we commit the record we see: [441] OracleSQLBuilder: SAVEPOINT 'BO_SP'[442] OracleSQLBuilder Executing, Lock 1 DML on: BOOKINGS (Update)[443] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[444] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[445] Update binding param 1: N[446] Where binding param 2: 1206[447] BookingsView1 notify COMMIT ... [448] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [449] EntityCache close prepared statement ....and as a result the changes are saved to the database, and the lock is released. Let's see what happens when we use the optimistic locking mode, this time to change the same BOOKINGS record CHARGEABLE column again.  As soon as we edit the record we see little activity in the logs, nothing to indicate any SQL statement, let alone a LOCK has been taken out on the row. However when we save our records by issuing a commit, the following is recorded in the logs: [509] OracleSQLBuilder: SAVEPOINT 'BO_SP'[510] OracleSQLBuilder Executing doEntitySelect on: BOOKINGS (true)[511] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[512] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[513] Where binding param 1: 1205[514] OracleSQLBuilder Executing, Lock 2 DML on: BOOKINGS (Update)[515] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[516] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[517] Update binding param 1: Y[518] Where binding param 2: 1205[519] BookingsView1 notify COMMIT ... [520] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [521] EntityCache close prepared statement Again even though we're seeing the midtier delay the LOCK statement until commit time, it is in fact occurring on line 412, and released as part of the commit issued on line 419.  Therefore with either optimistic or pessimistic locking a lock is indeed issued. Our conclusion at this point must be, unless there's the unlikely cause the LOCK statement is never really hitting the database, or the even less likely cause the database has a bug, then ADF does in fact take out a lock on the record before allowing the current user to update it.  So there's no way our phantom ADF developer could even modify the record if he tried without at least someone receiving a lock error. Hmm, we can only conclude the locking mode is a red herring and not the true cause of our problem.  Who is the phantom? At this point we'll need to conclude that the error message "JBO-25014: Another user has changed" is somehow legit, even though we don't understand yet what's causing it. This leads onto two further questions, how does ADF know another user has changed the row, and what's been changed anyway? To answer the first question, how does ADF know another user has changed the row, the Fusion Guide's section 4.10.11 How to Protect Against Losing Simultaneous Updated Data , that details the Entity Object Change-Indicator property, gives us the answer: At runtime the framework provides automatic "lost update" detection for entity objects to ensure that a user cannot unknowingly modify data that another user has updated and committed in the meantime. Typically, this check is performed by comparing the original values of each persistent entity attribute against the corresponding current column values in the database at the time the underlying row is locked. Before updating a row, the entity object verifies that the row to be updated is still consistent with the current state of the database.  The guide further suggests to make this solution more efficient: You can make the lost update detection more efficient by identifying any attributes of your entity whose values you know will be updated whenever the entity is modified. Typical candidates include a version number column or an updated date column in the row.....To detect whether the row has been modified since the user queried it in the most efficient way, select the Change Indicator option to compare only the change-indicator attribute values. We now know that ADF BC doesn't use the locking mechanism at all to protect the current user against updates, but rather it keeps a copy of the original record fetched, separate to the user changed version of the record, and it compares the original record against the one in the database when the lock is taken out.  If values don't match, be it the default compare-all-columns behaviour, or the more efficient Change Indicator mechanism, ADF BC will throw the JBO-25014 error. This leaves one last question.  Now we know the mechanism under which ADF identifies a changed row, what we don't know is what's changed and who changed it? The real culprit What's changed?  We know the record in the mid-tier has been changed by the user, however ADF doesn't use the changed record in the mid-tier to compare to the database record, but rather a copy of the original record before it was changed.  This leaves us to conclude the database record has changed, but how and by who? There are three potential causes: Database triggers The database trigger among other uses, can be configured to fire PLSQL code on a database table insert, update or delete.  In particular in an insert or update the trigger can override the value assigned to a particular column.  The trigger execution is actioned by the database on behalf of the user initiating the insert or update action. Why this causes the issue specific to our ADF use, is when we insert or update a record in the database via ADF, ADF keeps a copy of the record written to the database.  However the cached record is instantly out of date as the database triggers have modified the record that was actually written to the database.  Thus when we update the record we just inserted or updated for a second time to the database, ADF compares its original copy of the record to that in the database, and it detects the record has been changed – giving us JBO-25014. This is probably the most common cause of this problem. Default values A second reason this issue can occur is another database feature, default column values.  When creating a database table the schema designer can define default values for specific columns.  For example a CREATED_BY column could be set to SYSDATE, or a flag column to Y or N.  Default values are only used by the database when a user inserts a new record and the specific column is assigned NULL.  The database in this case will overwrite the column with the default value. As per the database trigger section, it then becomes apparent why ADF chokes on this feature, though it can only specifically occur in an insert-commit-update-commit scenario, not the update-commit-update-commit scenario. Instead of trigger views I must admit I haven't double checked this scenario but it seems plausible, that of the Oracle database's instead of trigger view (sometimes referred to as instead of views).  A view in the database is based on a query, and dependent on the queries complexity, may support insert, update and delete functionality to a limited degree.  In order to support fully insertable, updateable and deletable views, Oracle introduced the instead of view, that gives the view designer the ability to not only define the view query, but a set of programmatic PLSQL triggers where the developer can define their own logic for inserts, updates and deletes. While this provides the database programmer a very powerful feature, it can cause issues for our ADF application.  On inserting or updating a record in the instead of view, the record and it's data that goes in is not necessarily the data that comes out when ADF compares the records, as the view developer has the option to practically do anything with the incoming data, including throwing it away or pushing it to tables which aren't used by the view underlying query for fetching the data. Readers are at this point reminded that this article is specifically about how the JBO-25014 error occurs in the context of 1 developer on an isolated database.  The article is not considering how the error occurs in a production environment where there are multiple users who can cause this error in a legitimate fashion.  Assuming none of the above features are the cause of the problem, and optimistic locking is turned on (this error is not possible if pessimistic locking is the default mode *and* none of the previous causes are possible), JBO-25014 is quite feasible in a production ADF application if 2 users modify the same record. At this point under project timelines pressure, the obvious fix for developers is to drop both database triggers and default values from the underlying tables.  However we must be careful that these legacy constructs aren't used and assumed to be in place by other legacy systems.  Dropping the database triggers or default value that the existing Oracle Forms  applications assumes and requires to be in place could cause unexpected behaviour and bugs in the Forms application.  Proficient software engineers would recognize such a change may require a partial or full regression test of the existing legacy system, a potentially costly and timely exercise, not ideal. Solving the mystery once and for all Luckily ADF has built in functionality to deal with this issue, though it's not a surprise, as Oracle as the author of ADF also built the database, and are fully aware of the Oracle database's feature set.  At the Entity Object attribute level, the Refresh After Insert and Refresh After Update properties.  Simply selecting these instructs ADF BC after inserting or updating a record to the database, to expect the database to modify the said attributes, and read a copy of the changed attributes back into its cached mid-tier record.  Thus next time the developer modifies the current record, the comparison between the mid-tier record and the database record match, and JBO-25014: Another user has changed" is no longer an issue. [Post edit - as per the comment from Oracle's Steven Davelaar below, as he correctly points out the above solution will not work for instead-of-triggers views as it relies on SQL RETURNING clause which is incompatible with this type of view] Alternatively you can set the Change Indicator on one of the attributes.  This will work as long as the relating column for the attribute in the database itself isn't inadvertently updated.  In turn you're possibly just masking the issue rather than solving it, because if another developer turns the Change Indicator back on the original issue will return.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 130 131 132 133 134 135 136 137 138 139 140 141  | Next Page >