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  • SOLVED: deploying applications that use LINQ to Entities.

    - by Luiscencio
    HI COMUNITY!!!! I want to use L2E since it s very convenient to my company's apps, I created a demo project, the demo does run on every machine but when I, lets say, press a button that has some code that uses the entity I get this error: specified store provider cannot be found in the configuration, or is not valid. note that I get this error only on machines that does not have VS2008 installed, on these machines (the ones with VS2008) the demo works well. any advice is appreciated. I am using MySql server with Mysql Conector 6.3 and the model is created with ADO.Net entitiy model. EDIT here is the complete error trace: See the end of this message for details on invoking just-in-time (JIT) debugging instead of this dialog box. ************** Exception Text ************** System.ArgumentException: The specified store provider cannot be found in the configuration, or is not valid. ---> System.ArgumentException: Unable to find the requested .Net Framework Data Provider. It may not be installed. at System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName) at System.Data.EntityClient.EntityConnection.GetFactory(String providerString) --- End of inner exception stack trace --- at System.Data.EntityClient.EntityConnection.GetFactory(String providerString) at System.Data.EntityClient.EntityConnection.ChangeConnectionString(String newConnectionString) at System.Data.EntityClient.EntityConnection..ctor(String connectionString) at System.Data.Objects.ObjectContext.CreateEntityConnection(String connectionString) at System.Data.Objects.ObjectContext..ctor(String connectionString, String defaultContainerName) at Projects.projectsEntities..ctor() at Projects.frmProjecstMain.btnGenerarProyectoDeGarantias_Click(Object sender, EventArgs e) at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e) at System.Windows.Forms.ToolStripButton.OnClick(EventArgs e) at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e) at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e) at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met) at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met) at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ToolStrip.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) ************** Loaded Assemblies ************** mscorlib Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3603 (GDR.050727-3600) CodeBase: file:///c:/WINDOWS/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll ---------------------------------------- Projects Assembly Version: 1.0.0.0 Win32 Version: 1.0.0.0 CodeBase: file:///C:/Documents%20and%20Settings/jessica.carreon/Local%20Settings/Apps/2.0/1MLH514G.07M/RGBATG69.8AR/proj..tion_b0cb148e1dc400e0_0001.0000_738d35d08c548573/Projects.exe ---------------------------------------- System.Windows.Forms Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll ---------------------------------------- System Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll ---------------------------------------- System.Drawing Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll ---------------------------------------- MySql.Data Assembly Version: 6.3.0.0 Win32 Version: 6.3.0.0 CodeBase: file:///C:/Documents%20and%20Settings/jessica.carreon/Local%20Settings/Apps/2.0/1MLH514G.07M/RGBATG69.8AR/proj..tion_b0cb148e1dc400e0_0001.0000_738d35d08c548573/MySql.Data.DLL ---------------------------------------- System.Data Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.Data/2.0.0.0__b77a5c561934e089/System.Data.dll ---------------------------------------- System.Transactions Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.Transactions/2.0.0.0__b77a5c561934e089/System.Transactions.dll ---------------------------------------- System.Xml Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3082 (QFE.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll ---------------------------------------- System.Data.Entity Assembly Version: 3.5.0.0 Win32 Version: 3.5.30729.1 built by: SP CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Data.Entity/3.5.0.0__b77a5c561934e089/System.Data.Entity.dll ---------------------------------------- System.Core Assembly Version: 3.5.0.0 Win32 Version: 3.5.30729.1 built by: SP CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Core/3.5.0.0__b77a5c561934e089/System.Core.dll ---------------------------------------- System.Configuration Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll ---------------------------------------- System.EnterpriseServices Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.EnterpriseServices/2.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll ---------------------------------------- Microsoft.VisualBasic Assembly Version: 8.0.0.0 Win32 Version: 8.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Microsoft.VisualBasic/8.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll ---------------------------------------- ************** JIT Debugging ************** To enable just-in-time (JIT) debugging, the .config file for this application or computer (machine.config) must have the jitDebugging value set in the system.windows.forms section. The application must also be compiled with debugging enabled. For example: <configuration> <system.windows.forms jitDebugging="true" /> </configuration> When JIT debugging is enabled, any unhandled exception will be sent to the JIT debugger registered on the computer rather than be handled by this dialog box. here is the app.config: <?xml version="1.0" encoding="utf-8"?> <configuration> <configSections> </configSections> <connectionStrings> <add name="Projects.Properties.Settings.projectsConnectionString" connectionString="server=file-server;user id=root;database=projects" providerName="MySql.Data.MySqlClient" /> <add name="Projects.Properties.Settings.projectsBELO" connectionString="server=benitoldesk;user id=root;Password=ADMIN;persist security info=True;database=projects" providerName="MySql.Data.MySqlClient" /> <add name="projectsEntities" connectionString="metadata=res://*/projects.csdl|res://*/projects.ssdl|res://*/projects.msl;provider=MySql.Data.MySqlClient;provider connection string=&quot;server=file-server;User Id=root;database=projects;password=admin44ss04i)j0;Persist Security Info=True&quot;" providerName="System.Data.EntityClient" /> </connectionStrings> <appSettings> <add key="SecurityKey" value="Benito Lopez Dominguez" /> <add key="ClientSettingsProvider.ServiceUri" value="" /> </appSettings> <system.web> <membership defaultProvider="ClientAuthenticationMembershipProvider"> <providers> <add name="ClientAuthenticationMembershipProvider" type="System.Web.ClientServices.Providers.ClientFormsAuthenticationMembershipProvider, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" serviceUri="" /> </providers> </membership> <roleManager defaultProvider="ClientRoleProvider" enabled="true"> <providers> <add name="ClientRoleProvider" type="System.Web.ClientServices.Providers.ClientRoleProvider, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" serviceUri="" cacheTimeout="86400" /> </providers> </roleManager> </system.web> </configuration>

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  • HELP: deploying applications that use LINQ to Entities.

    - by Luiscencio
    HI COMUNITY!!!! I want to use L2E since it s very convenient to my company's apps, I created a demo project, the demo does run on every machine but when I, lets say, press a button that has some code that uses the entity I get this error: specified store provider cannot be found in the configuration, or is not valid. note that I get this error only on machines that does not have VS2008 installed, on these machines (the ones with VS2008) the demo works well. any advice is appreciated. I am using MySql server with Mysql Conector 6.3 and the model is created with ADO.Net entitiy model. EDIT here is the complete error trace: See the end of this message for details on invoking just-in-time (JIT) debugging instead of this dialog box. ************** Exception Text ************** System.ArgumentException: The specified store provider cannot be found in the configuration, or is not valid. ---> System.ArgumentException: Unable to find the requested .Net Framework Data Provider. It may not be installed. at System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName) at System.Data.EntityClient.EntityConnection.GetFactory(String providerString) --- End of inner exception stack trace --- at System.Data.EntityClient.EntityConnection.GetFactory(String providerString) at System.Data.EntityClient.EntityConnection.ChangeConnectionString(String newConnectionString) at System.Data.EntityClient.EntityConnection..ctor(String connectionString) at System.Data.Objects.ObjectContext.CreateEntityConnection(String connectionString) at System.Data.Objects.ObjectContext..ctor(String connectionString, String defaultContainerName) at Projects.projectsEntities..ctor() at Projects.frmProjecstMain.btnGenerarProyectoDeGarantias_Click(Object sender, EventArgs e) at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e) at System.Windows.Forms.ToolStripButton.OnClick(EventArgs e) at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e) at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e) at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met) at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met) at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ToolStrip.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) ************** Loaded Assemblies ************** mscorlib Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3603 (GDR.050727-3600) CodeBase: file:///c:/WINDOWS/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll ---------------------------------------- Projects Assembly Version: 1.0.0.0 Win32 Version: 1.0.0.0 CodeBase: file:///C:/Documents%20and%20Settings/jessica.carreon/Local%20Settings/Apps/2.0/1MLH514G.07M/RGBATG69.8AR/proj..tion_b0cb148e1dc400e0_0001.0000_738d35d08c548573/Projects.exe ---------------------------------------- System.Windows.Forms Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll ---------------------------------------- System Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll ---------------------------------------- System.Drawing Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll ---------------------------------------- MySql.Data Assembly Version: 6.3.0.0 Win32 Version: 6.3.0.0 CodeBase: file:///C:/Documents%20and%20Settings/jessica.carreon/Local%20Settings/Apps/2.0/1MLH514G.07M/RGBATG69.8AR/proj..tion_b0cb148e1dc400e0_0001.0000_738d35d08c548573/MySql.Data.DLL ---------------------------------------- System.Data Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.Data/2.0.0.0__b77a5c561934e089/System.Data.dll ---------------------------------------- System.Transactions Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.Transactions/2.0.0.0__b77a5c561934e089/System.Transactions.dll ---------------------------------------- System.Xml Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3082 (QFE.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll ---------------------------------------- System.Data.Entity Assembly Version: 3.5.0.0 Win32 Version: 3.5.30729.1 built by: SP CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Data.Entity/3.5.0.0__b77a5c561934e089/System.Data.Entity.dll ---------------------------------------- System.Core Assembly Version: 3.5.0.0 Win32 Version: 3.5.30729.1 built by: SP CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Core/3.5.0.0__b77a5c561934e089/System.Core.dll ---------------------------------------- System.Configuration Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll ---------------------------------------- System.EnterpriseServices Assembly Version: 2.0.0.0 Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.EnterpriseServices/2.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll ---------------------------------------- Microsoft.VisualBasic Assembly Version: 8.0.0.0 Win32 Version: 8.0.50727.3053 (netfxsp.050727-3000) CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Microsoft.VisualBasic/8.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll ---------------------------------------- ************** JIT Debugging ************** To enable just-in-time (JIT) debugging, the .config file for this application or computer (machine.config) must have the jitDebugging value set in the system.windows.forms section. The application must also be compiled with debugging enabled. For example: <configuration> <system.windows.forms jitDebugging="true" /> </configuration> When JIT debugging is enabled, any unhandled exception will be sent to the JIT debugger registered on the computer rather than be handled by this dialog box. here is the app.config: <?xml version="1.0" encoding="utf-8"?> <configuration> <configSections> </configSections> <connectionStrings> <add name="Projects.Properties.Settings.projectsConnectionString" connectionString="server=file-server;user id=root;database=projects" providerName="MySql.Data.MySqlClient" /> <add name="Projects.Properties.Settings.projectsBELO" connectionString="server=benitoldesk;user id=root;Password=ADMIN;persist security info=True;database=projects" providerName="MySql.Data.MySqlClient" /> <add name="projectsEntities" connectionString="metadata=res://*/projects.csdl|res://*/projects.ssdl|res://*/projects.msl;provider=MySql.Data.MySqlClient;provider connection string=&quot;server=file-server;User Id=root;database=projects;password=admin44ss04i)j0;Persist Security Info=True&quot;" providerName="System.Data.EntityClient" /> </connectionStrings> <appSettings> <add key="SecurityKey" value="Benito Lopez Dominguez" /> <add key="ClientSettingsProvider.ServiceUri" value="" /> </appSettings> <system.web> <membership defaultProvider="ClientAuthenticationMembershipProvider"> <providers> <add name="ClientAuthenticationMembershipProvider" type="System.Web.ClientServices.Providers.ClientFormsAuthenticationMembershipProvider, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" serviceUri="" /> </providers> </membership> <roleManager defaultProvider="ClientRoleProvider" enabled="true"> <providers> <add name="ClientRoleProvider" type="System.Web.ClientServices.Providers.ClientRoleProvider, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" serviceUri="" cacheTimeout="86400" /> </providers> </roleManager> </system.web> </configuration>

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  • Announcing Entity Framework Code-First (CTP5 release)

    - by ScottGu
    This week the data team released the CTP5 build of the new Entity Framework Code-First library.  EF Code-First enables a pretty sweet code-centric development workflow for working with data.  It enables you to: Develop without ever having to open a designer or define an XML mapping file Define model objects by simply writing “plain old classes” with no base classes required Use a “convention over configuration” approach that enables database persistence without explicitly configuring anything Optionally override the convention-based persistence and use a fluent code API to fully customize the persistence mapping I’m a big fan of the EF Code-First approach, and wrote several blog posts about it this summer: Code-First Development with Entity Framework 4 (July 16th) EF Code-First: Custom Database Schema Mapping (July 23rd) Using EF Code-First with an Existing Database (August 3rd) Today’s new CTP5 release delivers several nice improvements over the CTP4 build, and will be the last preview build of Code First before the final release of it.  We will ship the final EF Code First release in the first quarter of next year (Q1 of 2011).  It works with all .NET application types (including both ASP.NET Web Forms and ASP.NET MVC projects). Installing EF Code First You can install and use EF Code First CTP5 using one of two ways: Approach 1) By downloading and running a setup program.  Once installed you can reference the EntityFramework.dll assembly it provides within your projects.      or: Approach 2) By using the NuGet Package Manager within Visual Studio to download and install EF Code First within a project.  To do this, simply bring up the NuGet Package Manager Console within Visual Studio (View->Other Windows->Package Manager Console) and type “Install-Package EFCodeFirst”: Typing “Install-Package EFCodeFirst” within the Package Manager Console will cause NuGet to download the EF Code First package, and add it to your current project: Doing this will automatically add a reference to the EntityFramework.dll assembly to your project:   NuGet enables you to have EF Code First setup and ready to use within seconds.  When the final release of EF Code First ships you’ll also be able to just type “Update-Package EFCodeFirst” to update your existing projects to use the final release. EF Code First Assembly and Namespace The CTP5 release of EF Code First has an updated assembly name, and new .NET namespace: Assembly Name: EntityFramework.dll Namespace: System.Data.Entity These names match what we plan to use for the final release of the library. Nice New CTP5 Improvements The new CTP5 release of EF Code First contains a bunch of nice improvements and refinements. Some of the highlights include: Better support for Existing Databases Built-in Model-Level Validation and DataAnnotation Support Fluent API Improvements Pluggable Conventions Support New Change Tracking API Improved Concurrency Conflict Resolution Raw SQL Query/Command Support The rest of this blog post contains some more details about a few of the above changes. Better Support for Existing Databases EF Code First makes it really easy to create model layers that work against existing databases.  CTP5 includes some refinements that further streamline the developer workflow for this scenario. Below are the steps to use EF Code First to create a model layer for the Northwind sample database: Step 1: Create Model Classes and a DbContext class Below is all of the code necessary to implement a simple model layer using EF Code First that goes against the Northwind database: EF Code First enables you to use “POCO” – Plain Old CLR Objects – to represent entities within a database.  This means that you do not need to derive model classes from a base class, nor implement any interfaces or data persistence attributes on them.  This enables the model classes to be kept clean, easily testable, and “persistence ignorant”.  The Product and Category classes above are examples of POCO model classes. EF Code First enables you to easily connect your POCO model classes to a database by creating a “DbContext” class that exposes public properties that map to the tables within a database.  The Northwind class above illustrates how this can be done.  It is mapping our Product and Category classes to the “Products” and “Categories” tables within the database.  The properties within the Product and Category classes in turn map to the columns within the Products and Categories tables – and each instance of a Product/Category object maps to a row within the tables. The above code is all of the code required to create our model and data access layer!  Previous CTPs of EF Code First required an additional step to work against existing databases (a call to Database.Initializer<Northwind>(null) to tell EF Code First to not create the database) – this step is no longer required with the CTP5 release.  Step 2: Configure the Database Connection String We’ve written all of the code we need to write to define our model layer.  Our last step before we use it will be to setup a connection-string that connects it with our database.  To do this we’ll add a “Northwind” connection-string to our web.config file (or App.Config for client apps) like so:   <connectionStrings>          <add name="Northwind"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\northwind.mdf;User Instance=true"          providerName="System.Data.SqlClient" />   </connectionStrings> EF “code first” uses a convention where DbContext classes by default look for a connection-string that has the same name as the context class.  Because our DbContext class is called “Northwind” it by default looks for a “Northwind” connection-string to use.  Above our Northwind connection-string is configured to use a local SQL Express database (stored within the \App_Data directory of our project).  You can alternatively point it at a remote SQL Server. Step 3: Using our Northwind Model Layer We can now easily query and update our database using the strongly-typed model layer we just built with EF Code First. The code example below demonstrates how to use LINQ to query for products within a specific product category.  This query returns back a sequence of strongly-typed Product objects that match the search criteria: The code example below demonstrates how we can retrieve a specific Product object, update two of its properties, and then save the changes back to the database: EF Code First handles all of the change-tracking and data persistence work for us, and allows us to focus on our application and business logic as opposed to having to worry about data access plumbing. Built-in Model Validation EF Code First allows you to use any validation approach you want when implementing business rules with your model layer.  This enables a great deal of flexibility and power. Starting with this week’s CTP5 release, EF Code First also now includes built-in support for both the DataAnnotation and IValidatorObject validation support built-into .NET 4.  This enables you to easily implement validation rules on your models, and have these rules automatically be enforced by EF Code First whenever you save your model layer.  It provides a very convenient “out of the box” way to enable validation within your applications. Applying DataAnnotations to our Northwind Model The code example below demonstrates how we could add some declarative validation rules to two of the properties of our “Product” model: We are using the [Required] and [Range] attributes above.  These validation attributes live within the System.ComponentModel.DataAnnotations namespace that is built-into .NET 4, and can be used independently of EF.  The error messages specified on them can either be explicitly defined (like above) – or retrieved from resource files (which makes localizing applications easy). Validation Enforcement on SaveChanges() EF Code-First (starting with CTP5) now automatically applies and enforces DataAnnotation rules when a model object is updated or saved.  You do not need to write any code to enforce this – this support is now enabled by default.  This new support means that the below code – which violates our above rules – will automatically throw an exception when we call the “SaveChanges()” method on our Northwind DbContext: The DbEntityValidationException that is raised when the SaveChanges() method is invoked contains a “EntityValidationErrors” property that you can use to retrieve the list of all validation errors that occurred when the model was trying to save.  This enables you to easily guide the user on how to fix them.  Note that EF Code-First will abort the entire transaction of changes if a validation rule is violated – ensuring that our database is always kept in a valid, consistent state. EF Code First’s validation enforcement works both for the built-in .NET DataAnnotation attributes (like Required, Range, RegularExpression, StringLength, etc), as well as for any custom validation rule you create by sub-classing the System.ComponentModel.DataAnnotations.ValidationAttribute base class. UI Validation Support A lot of our UI frameworks in .NET also provide support for DataAnnotation-based validation rules. For example, ASP.NET MVC, ASP.NET Dynamic Data, and Silverlight (via WCF RIA Services) all provide support for displaying client-side validation UI that honor the DataAnnotation rules applied to model objects. The screen-shot below demonstrates how using the default “Add-View” scaffold template within an ASP.NET MVC 3 application will cause appropriate validation error messages to be displayed if appropriate values are not provided: ASP.NET MVC 3 supports both client-side and server-side enforcement of these validation rules.  The error messages displayed are automatically picked up from the declarative validation attributes – eliminating the need for you to write any custom code to display them. Keeping things DRY The “DRY Principle” stands for “Do Not Repeat Yourself”, and is a best practice that recommends that you avoid duplicating logic/configuration/code in multiple places across your application, and instead specify it only once and have it apply everywhere. EF Code First CTP5 now enables you to apply declarative DataAnnotation validations on your model classes (and specify them only once) and then have the validation logic be enforced (and corresponding error messages displayed) across all applications scenarios – including within controllers, views, client-side scripts, and for any custom code that updates and manipulates model classes. This makes it much easier to build good applications with clean code, and to build applications that can rapidly iterate and evolve. Other EF Code First Improvements New to CTP5 EF Code First CTP5 includes a bunch of other improvements as well.  Below are a few short descriptions of some of them: Fluent API Improvements EF Code First allows you to override an “OnModelCreating()” method on the DbContext class to further refine/override the schema mapping rules used to map model classes to underlying database schema.  CTP5 includes some refinements to the ModelBuilder class that is passed to this method which can make defining mapping rules cleaner and more concise.  The ADO.NET Team blogged some samples of how to do this here. Pluggable Conventions Support EF Code First CTP5 provides new support that allows you to override the “default conventions” that EF Code First honors, and optionally replace them with your own set of conventions. New Change Tracking API EF Code First CTP5 exposes a new set of change tracking information that enables you to access Original, Current & Stored values, and State (e.g. Added, Unchanged, Modified, Deleted).  This support is useful in a variety of scenarios. Improved Concurrency Conflict Resolution EF Code First CTP5 provides better exception messages that allow access to the affected object instance and the ability to resolve conflicts using current, original and database values.  Raw SQL Query/Command Support EF Code First CTP5 now allows raw SQL queries and commands (including SPROCs) to be executed via the SqlQuery and SqlCommand methods exposed off of the DbContext.Database property.  The results of these method calls can be materialized into object instances that can be optionally change-tracked by the DbContext.  This is useful for a variety of advanced scenarios. Full Data Annotations Support EF Code First CTP5 now supports all standard DataAnnotations within .NET, and can use them both to perform validation as well as to automatically create the appropriate database schema when EF Code First is used in a database creation scenario.  Summary EF Code First provides an elegant and powerful way to work with data.  I really like it because it is extremely clean and supports best practices, while also enabling solutions to be implemented very, very rapidly.  The code-only approach of the library means that model layers end up being flexible and easy to customize. This week’s CTP5 release further refines EF Code First and helps ensure that it will be really sweet when it ships early next year.  I recommend using NuGet to install and give it a try today.  I think you’ll be pleasantly surprised by how awesome it is. Hope this helps, Scott

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  • Entity Framework Code First: Get Entities From Local Cache or the Database

    - by Ricardo Peres
    Entity Framework Code First makes it very easy to access local (first level) cache: you just access the DbSet<T>.Local property. This way, no query is sent to the database, only performed in already loaded entities. If you want to first search local cache, then the database, if no entries are found, you can use this extension method: 1: public static class DbContextExtensions 2: { 3: public static IQueryable<T> LocalOrDatabase<T>(this DbContext context, Expression<Func<T, Boolean>> expression) where T : class 4: { 5: IEnumerable<T> localResults = context.Set<T>().Local.Where(expression.Compile()); 6:  7: if (localResults.Any() == true) 8: { 9: return (localResults.AsQueryable()); 10: } 11:  12: IQueryable<T> databaseResults = context.Set<T>().Where(expression); 13:  14: return (databaseResults); 15: } 16: }

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  • Entity System and rendering

    - by hayer
    Okey, what I know so far; The entity contains a component(data-storage) which holds information like; - Texture/sprite - Shader - etc And then I have a renderer system which draws all this. But what I don't understand is how the renderer should be designed. Should I have one component for each "visual type". One component without shader, one with shader, etc? Just need some input on whats the "correct way" to do this. Tips and pitfalls to watch out for.

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  • Problem with Mapping Linq-to-Sql on different Types

    - by csharpnoob
    Hi, maybe someone can help. I want to have on mapped Linq-Class different Datatype. This is working: private System.Nullable<short> _deleted = 1; [Column(Storage = "_deleted", Name = "deleted", DbType = "SmallInt", CanBeNull = true)] public System.Nullable<short> deleted { get { return this._deleted; } set { this._deleted = value; } } Sure thing. But no when i want to place some logic for boolean, like this: private System.Nullable<short> _deleted = 1; [Column(Storage = "_deleted", Name = "deleted", DbType = "SmallInt", CanBeNull = true)] public bool deleted { get { if (this._deleted == 1) { return true; } return false; } set { if(value == true) { this._deleted = (short)1; }else { this._deleted = (short)0; } } } I get always runtime error: [TypeLoadException: GenericArguments[2], "System.Nullable`1[System.Int16]", on 'System.Data.Linq.Mapping.PropertyAccessor+Accessor`3[T,V,V2]' violates the constraint of type parameter 'V2'.] I can't change the database to bit.. I need to have casting in mapping class.

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  • c# linq to xml to list

    - by WtFudgE
    I was wondering if there is a way to get a list of results into a list with linq to xml. If I would have the following xml for example: <?xml version="1.0"?> <Sports xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <SportPages> <SportPage type="test"> <LinkPage> <IDList> <string>1</string> <string>2</string> </IDList> </LinkPage> </SportPage> </SportPages> </Sports> How could I get a list of strings from the IDList? I'm fairly new to linq to xml so I just tried some stuff out, I'm currently at this point: var IDs = from sportpage in xDoc.Descendants("SportPages").Descendants("SportPage") where sportpage.Attribute("type").Value == "Karate" select new { ID = sportpage.Element("LinkPage").Element("IDList").Elements("string") }; But the var is to chaotic to read decently. Isn't there a way I could just get a list of strings from this? Thanks

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  • ASP MVC C#: LINQ Foreign Key Constraint conflicts

    - by wh0emPah
    I'm having a problem with LINQ. I have 2 tables (Parent-child relation) Table1: Events (EventID, Description) Table2: Groups (GroupID, EventID(FK), Description) Now i want to create an Event an and a child. Event e = new Event(); e.Description = "test"; Datacontext.Events.InsertOnSubmit(event) Group g = new Group(); g.Description = "test2"; g.EventID = e.EventID; Datacontext.Groups.InsertOnSubmit(g); Datacontext.SubmitChanges(); When i debug, i can see that after inserting the event. the EventID has gotten a new value (auto increment). But when Datacontext.SubmitChanges(); gets called. I get the following exception "The INSERT statement conflicted with the FOREIGN KEY constraint ... I know this can be solved by creating a relation in the LINQ diagram between Events and groups. And then setting the entity itself. But i don't want to load the events everytime i ask a list of groups. All i need is some way that when inserting the group fails, the event insert won't be comitted in the database. Sorry if this is a bit unclear, My english isn't really good. Thanks in advance!

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  • LINQ self referencing query

    - by Chris
    I have the following SQL query: select p1.[id], p1.[useraccountid], p1.[subject], p1.[message], p1.[views], p1.[parentid], case when p2.[created] is null then p1.[created] else p2.[created] end as LastUpdate from forumposts p1 left join ( select parentid, max(created) as [created] from forumposts group by parentid ) p2 on p2.parentid = p1.id where p1.[parentid] is null order by LastUpdate desc Using the following class: public class ForumPost : PersistedObject { public int Views { get; set; } public string Message { get; set; } public string Subject { get; set; } public ForumPost Parent { get; set; } public UserAccount UserAccount { get; set; } public IList<ForumPost> Replies { get; set; } } How would I replicate such a query in LINQ? I've tried several variations, but I seem unable to get the correct join syntax. Is this simply a case of a query that is too complicated for LINQ? Can it be done using nested queries some how? The purpose of the query is to find the most recently updated posts i.e. replying to a post would bump it to the top of the list. Replies are defined by the ParentID column, which is self-referencing.

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  • Tracking Down a Stack Overflow in My Linq Query

    - by Lazarus
    I've written the following Linq query: IQueryable<ISOCountry> entries = (from e in competitorRepository.Competitors join c in countries on e.countryID equals c.isoCountryCode where !e.Deleted orderby c.isoCountryCode select new ISOCountry() { isoCountryCode = e.countryID, Name = c.Name }).Distinct(); The objective is to retrieve a list of the countries represented by the competitors found in the system. 'countries' is an array of ISOCountry objects explicitly created and returned as an IQueryable (ISOCountry is an object of just two strings, isoCountryCode and Name). Competitors is an IQueryable which is bound to a database table through Linq2SQL though I created the objects from scratch and used the Linq data mapping decorators. For some reason this query causes a stack overflow when the system tries to execute it. I've no idea why, I've tried trimming the Distinct, returning an anonymous type of the two strings, using 'select c', all result in the overflow. The e.CountryID value is populated from a dropdown that was in itself populated from the IQueryable so I know the values are appropriate but even if not I wouldn't expect a stack overflow. Can anyone explain why the overflow is occurring or give good speculation as to why it might be happening? EDIT As requested, code for ISOCountry: public class ISOCountry { public string isoCountryCode { get; set; } public string Name { get; set; } }

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  • LINQ to XML via C#

    - by user70192
    Hello, I'm new to LINQ. I understand it's purpose. But I can't quite figure it out. I have an XML set that looks like the following: <Results> <Result> <ID>1</ID> <Name>John Smith</Name> <EmailAddress>[email protected]</EmailAddress> </Result> <Result> <ID>2</ID> <Name>Bill Young</Name> <EmailAddress>[email protected]</EmailAddress> </Result> </Results> I have loaded this XML into an XDocument as such: string xmlText = GetXML(); XDocument xml = XDocument.Parse(xmlText); Now, I'm trying to get the results into POCO format. In an effort to do this, I'm currently using: var objects = from results in xml.Descendants("Results") select new Results // I'm stuck How do I get a collection of Result elements via LINQ? I'm particularly confused about navigating the XML structure at this point in my code. Thank you!

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  • Getting values from DataGridView back to XDocument (using LINQ-to-XML)

    - by Pretzel
    Learning LINQ has been a lot of fun so far, but despite reading a couple books and a bunch of online resources on the topic, I still feel like a total n00b. Recently, I just learned that if my query returns an Anonymous type, the DataGridView I'm populating will be ReadOnly (because, apparently Anonymous types are ReadOnly.) Right now, I'm trying to figure out the easiest way to: Get a subset of data from an XML file into a DataGridView, Allow the user to edit said data, Stick the changed data back into the XML file. So far I have Steps 1 and 2 figured out: public class Container { public string Id { get; set; } public string Barcode { get; set; } public float Quantity { get; set; } } // For use with the Distinct() operator public class ContainerComparer : IEqualityComparer<Container> { public bool Equals(Container x, Container y) { return x.Id == y.Id; } public int GetHashCode(Container obj) { return obj.Id.GetHashCode(); } } var barcodes = (from src in xmldoc.Descendants("Container") where src.Descendants().Count() > 0 select new Container { Id = (string)src.Element("Id"), Barcode = (string)src.Element("Barcode"), Quantity = float.Parse((string)src.Element("Quantity").Attribute("value")) }).Distinct(new ContainerComparer()); dataGridView1.DataSource = barcodes.ToList(); This works great at getting the data I want from the XML into the DataGridView so that the user has a way to manipulate the values. Upon doing a Step-thru trace of my code, I'm finding that the changes to the values made in DataGridView are not bound to the XDocument object and as such, do not propagate back. How do we take care of Step 3? (getting the data back to the XML) Is it possible to Bind the XML directly to the DataGridView? Or do I have to write another LINQ statement to get the data from the DGV back to the XDocument? Suggstions?

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  • Linq join with an inner collection

    - by bronze
    Hi, I am trying a LINQ to Object query on 2 collections Customer.Orders Branches.Pending.Orders (Collection within a collection) I want to output each branch which is yet to deliver any order of the customer. var match = from order in customer.Orders join branch in Branches on order equals branch.Pending.Orders select branch; This does not work, I get : The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'GroupJoin'. From my search, I think this is because Order or collection of Orders does not implement equals. If this query worked, it will still be wrong, as it will return a branch if the customer's and pending orders match exactly. I want a result if any of the order matches. I am learning Linq, and looking for a approach to address such issues, rather than the solution itself. I would have done this in SQL like this; SELECT b.branch_name from Customers c, Branches b, Orders o WHERE c.customer_id = o.customer_id AND o.branch_id = b.branch_id AND c.customer_id = 'my customer' AND o.order_status = 'pending'

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  • Linq is returning too many results when joined

    - by KallDrexx
    In my schema I have two database tables. relationships and relationship_memberships. I am attempting to retrieve all the entries from the relationship table that have a specific member in it, thus having to join it with the relationship_memberships table. I have the following method in my business object: public IList<DBMappings.relationships> GetRelationshipsByObjectId(int objId) { var results = from r in _context.Repository<DBMappings.relationships>() join m in _context.Repository<DBMappings.relationship_memberships>() on r.rel_id equals m.rel_id where m.obj_id == objId select r; return results.ToList<DBMappings.relationships>(); } _Context is my generic repository using code based on the code outlined here. The problem is I have 3 records in the relationships table, and 3 records in the memberships table, each membership tied to a different relationship. 2 membership records have an obj_id value of 2 and the other is 3. I am trying to retrieve a list of all relationships related to object #2. When this linq runs, _context.Repository<DBMappings.relationships>() returns the correct 3 records and _context.Repository<DBMappings.relationship_memberships>() returns 3 records. However, when the results.ToList() executes, the resulting list has 2 issues: 1) The resulting list contains 6 records, all of type DBMappings.relationships(). Upon further inspection there are 2 for each real relationship record, both are an exact copy of each other. 2) All relationships are returned, even if m.obj_id == 3, even though objId variable is correctly passed in as 2. Can anyone see what's going on because I've spent 2 days looking at this code and I am unable to understand what is wrong. I have joins in other linq queries that seem to be working great, and my unit tests show that they are still working, so I must be doing something wrong with this. It seems like I need an extra pair of eyes on this one :)

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  • Using conditionals in Linq Programatically

    - by Mike B
    I was just reading a recent question on using conditionals in Linq and it reminded me of an issue I have not been able to resolve. When building Linq to SQL queries programatically how can this be done when the number of conditionals is not known until runtime? For instance in the code below the first clause creates an IQueryable that, if executed, would select all the tasks (called issues) in the database, the 2nd clause will refine that to just issues assigned to one department if one has been selected in a combobox (Which has it's selected item bound to the departmentToShow property). How could I do this using the selectedItems collection instead? IQueryable<Issue> issuesQuery; // Will select all tasks issuesQuery = from i in db.Issues orderby i.IssDueDate, i.IssUrgency select i; // Filters out all other Departments if one is selected if (departmentToShow != "All") { issuesQuery = from i in issuesQuery where i.IssDepartment == departmentToShow select i; } By the way, the above code is simplified, in the actual code there are about a dozen clauses that refine the query based on the users search and filter settings.

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  • Can't combine "LINQ Join" with other tables

    - by FullmetalBoy
    The main problem is that I recieve the following message: "base {System.SystemException} = {"Unable to create a constant value of type 'BokButik1.Models.Book-Author'. Only primitive types ('such as Int32, String, and Guid') are supported in this context."}" based on this LinQ code: IBookRepository myIBookRepository = new BookRepository(); var allBooks = myIBookRepository.HamtaAllaBocker(); IBok_ForfattareRepository myIBok_ForfattareRepository = new Bok_ForfattareRepository(); var Book-Authors = myIBok_ForfattareRepository.HamtaAllaBok_ForfattareNummer(); var q = from booknn in allBooks join Book-Authornn in Book-Authors on booknn.BookID equals Book-Authornn.BookID select new { booknn.title, Book-AuthorID }; How shall I solve this problem to get a class instance that contain with property title and Book-AuthorID? // Fullmetalboy I also have tried making some dummy by using "allbooks" relation with Code Samples from the address http://www.hookedonlinq.com/JoinOperator.ashx. Unfortunately, still same problem. I also have taken account to Int32 due to entity framework http://msdn.microsoft.com/en-us/library/bb896317.aspx. Unfortunatley, still same problem. Using database with 3 tables and one of them is a many to many relationship. This database is used in relation with entity framework Book-Author Book-Author (int) BookID (int) Forfattare (int) Book BookID (int) title (string) etc etc etc

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  • Delaying LINQ to SQL Select Query Execution

    - by Maxim Z.
    I'm building an ASP.NET MVC site that uses LINQ to SQL. In my search method that has some required and some optional parameters, I want to build a LINQ query while testing for the existence of those optional parameters. Here's what I'm currently thinking: using(var db = new DBDataContext()) { IQueryable<Listing> query = null; //Handle required parameter query = db.Listings.Where(l => l.Lat >= form.bounds.extent1.latitude && l.Lat <= form.bounds.extent2.latitude); //Handle optional parameter if (numStars != null) query = query.Where(l => l.Stars == (int)numStars); //Other parameters... //Execute query (does this happen here?) var result = query.ToList(); //Process query... Will this implementation "bundle" the where clauses and then execute the bundled query? If not, how should I implement this feature? Also, is there anything else that I can improve? Thanks in advance.

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  • LINQ to SQL: Reusable expression for property?

    - by coenvdwel
    Pardon me for being unable to phrase the title more exact. Basically, I have three LINQ objects linked to tables. One is Product, the other is Company and the last is a mapping table Mapping to store what Company sells which products and by which ID this Company refers to this Product. I am now retrieving a list of products as follows: var options = new DataLoadOptions(); options.LoadWith<Product>(p => p.Mappings); context.LoadOptions = options; var products = ( from p in context.Products select new { ProductID = p.ProductID, //BackendProductID = p.BackendProductID, BackendProductID = (p.Mappings.Count == 0) ? "None" : (p.Mappings.Count > 1) ? "Multiple" : p.Mappings.First().BackendProductID, Description = p.Description } ).ToList(); This does a single query retrieving the information I want. But I want to be able to move the logic behind the BackendProductID into the LINQ object so I can use the commented line instead of the annoyingly nested ternary operator statements for neatness and re-usability. So I added the following property to the Product object: public string BackendProductID { get { if (Mappings.Count == 0) return "None"; if (Mappings.Count > 1) return "Multiple"; return Mappings.First().BackendProductID; } } The list is still the same, but it now does a query for every single Product to get it's BackendProductID. The code is neater and re-usable, but the performance now is terrible. What I need is some kind of Expression or Delegate but I couldn't get my head around writing one. It always ended up querying for every single product, still. Any help would be appreciated!

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  • LINQ to objects: Is there

    - by Charles
    I cannot seem to find a way to have LINQ return the value from a specified accessor. I know the name of the accessors for each object, but am unsure if it is possible to pass the requested accessor as a variable or otherwise achieve the desired refactoring. Consider the following code snippet: // "value" is some object with accessors like: format, channels, language row = new List<String> { String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.format).ToArray()), String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.channels).ToArray()), String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.language).ToArray()), // ... } I'd like to refactor this into a method that uses the specified accessor, or perhaps pass a delegate, though I don't see how that could work. string niceRefactor(myObj myObject, string /* or whatever type */ ____ACCESSOR) { return String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.____ACCESSOR).ToArray()); } I have written a decent amount of C#, but am still new to the magic of LINQ. Is this the right approach? How would you refactor this?

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  • Linq generic Expression in query on "element" or on IQueryable (multiple use)

    - by Bogdan Maxim
    Hi, I have the following expression public static Expression<Func<T, bool>> JoinByDateCheck<T>(T entity, DateTime dateToCheck) where T : IDateInterval { return (entityToJoin) => entityToJoin.FromDate.Date <= dateToCheck.Date && (entityToJoin.ToDate == null || entityToJoin.ToDate.Value.Date >= dateToCheck.Date); } IDateInterval interface is defined like this: interface IDateInterval { DateTime FromDate {get;} DateTime? ToDate {get;} } and i need to apply it in a few ways: (1) Query on Linq2Sql Table: var q1 = from e in intervalTable where FunctionThatCallsJoinByDateCheck(e, constantDateTime) select e; or something like this: intervalTable.Where(FunctionThatCallsJoinByDateCheck(e, constantDateTime)) (2) I need to use it in some table joins (as linq2sql doesn't provide comparative join): var q2 = from e1 in t1 join e2 in t2 on e1.FK == e2.PK where OtherFunctionThatCallsJoinByDateCheck(e2, e1.FromDate) or var q2 = from e1 in t1 from e2 in t2 where e1.FK == e2.PK && OtherFunctionThatCallsJoinByDateCheck(e2, e1.FromDate) (3) I need to use it in some queries like this: var q3 = from e in intervalTable.FilterFunctionThatCallsJoinByDateCheck(constantDate); Dynamic linq is not something that I can use, so I have to stick to plain linq. Thank you Clarification: Initially I had just the last method (FilterFunctionThatCallsJoinByDateCheck(this IQueryable<IDateInterval> entities, DateTime dateConstant) ) that contained the code from the expression. The problem is that I get a SQL Translate exception if I write the code in a method and call it like that. All I want is to extend the use of this function to the where clause (see the second query in point 2)

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  • OrderBy Linq.Expression as parameter = (Of Func(Of T,IComparable)) to perform LinqToEntity is not working

    - by NicoJuicy
    I'd like to get this working: Call: (Count & Page are used for pagination, so Count = 20 and Page = 1 for example, for the first 20 values). Sorting should be by name LeverancierService.GetLeveranciers(Function(el) el.Name, Count, Page) Equivalent in c#: LeverancierService.GetLeveranciers(el= el.Name, Count, Page) Method that gives an error (parameters shown above): Public Overridable Function GetAllPaged(orderby As Expression(Of Func(Of T, IComparable)), ByVal Count As Integer, ByVal Page As Integer) As IEnumerable(Of T) Return dbset.OrderBy(orderby).Skip((Page - 1) * Count).Take(Count).ToList() End Function Already tried changing it to this, but it gives the same error: Public Overridable Function GetAllPaged(Of TOrderBy)(orderby As Expression(Of Func(Of T, TOrderBy)), ByVal Count As Integer, ByVal Page As Integer) As IEnumerable(Of T) Return dbset.OrderBy(orderby).Skip((Page - 1) * Count).Take(Count).ToList() End Function Error: Unable to cast the type 'System.String' to type 'System.IComparable'. LINQ to Entities only supports casting Entity Data Model primitive types. Any idea how to do this? Extra info: I'm in a DDD-layered application, so the parameter should stay the same as the called method is an overridden interface (eg. if i change this, i have to do this for 200 times or so, because it's in VB.Net and not in C# (= 1 change) ) I know there is a way to change the expression to a string and then use DLinq (= Dynamic Linq), but that's not how it should be.

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  • Inefficient 'ANY' LINQ clause

    - by Focus
    I have a query that pulls back a user's "feed" which is essentially all of their activity. If the user is logged in the query will be filtered so that the feed not only includes all of the specified user's data, but also any of their friends. The database structure includes an Actions table that holds the user that created the action and a UserFriends table which holds any pairing of friends using a FrienderId and FriendeeId column which map to UserIds. I have set up my LINQ query and it works fine to pull back the data I want, however, I noticed that the query gets turned into X number of CASE clauses in profiler where X is the number of total Actions in the database. This will obviously be horrible when the database has a user base larger than just me and 3 test users. Here's the SQL query I'm trying to achieve: select * from [Action] a where a.UserId = 'GUID' OR a.UserId in (SELECT FriendeeId from UserFriends uf where uf.FrienderId = 'GUID') OR a.UserId in (SELECT FrienderId from UserFriends uf where uf.FriendeeId = 'GUID') This is what I currently have as my LINQ query. feed = feed.Where(o => o.User.UserKey == user.UserKey || db.Users.Any(u => u.UserFriends.Any(ufr => ufr.Friender.UserKey == user.UserKey && ufr.isApproved) || db.Users.Any(u2 => u2.UserFriends.Any(ufr => ufr.Friendee.UserKey == user.UserKey && ufr.isApproved) ))); This query creates this: http://pastebin.com/UQhT90wh That shows up X times in the profile trace, once for each Action in the table. What am I doing wrong? Is there any way to clean this up?

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  • LINQ to SQL Queries odd Materialization

    - by ptoinson
    I ran across an interesting Linq to SQL, uh, feature, the other day. Perhaps someone can give me a logical explanation for the reasoning behind the results. Take the code below as my example which utilizes the AdventureWorks database setup in a Linq to SQL DataContext. This is a clip from my unit test. The resulting customer returned from a call to both CustomerQuery_Test_01() and CustomerQuery_Test_02() is the same. However, the query executed on the SQLServer are different is a major way. The method CustomerQuery_Test_01 us causing the entire Customer table to be materialized, which the call to CustomerQuery_Test_02 is only causing the single customer to be materialized. The resulting SQL Queries are at the bottom of this post. Anyone have a good reason for this? To me, it was highly non-intuitive. protected virtual Customer GetByPrimaryKey(Func<Customer, bool> keySelection) { AdventureWorksDataContext context = new AdventureWorksDataContext(); return (from r in context.Customers select r).SingleOrDefault(keySelection); } [TestMethod] public void CustomerQuery_Test_01() { Customer customer = GetByPrimaryKey(c => c.CustomerID == 2); } [TestMethod] public void CustomerQuery_Test_02() { AdventureWorksDataContext context = new AdventureWorksDataContext(); Customer customer = (from r in context.Customers select r).SingleOrDefault(c => c.CustomerID == 2); } Query for CustomerQuery_Test_01 (notice the lack of a where clause) SELECT [t0].[CustomerID], [t0].[NameStyle], [t0].[Title], [t0].[FirstName], [t0].[MiddleName], [t0].[LastName], [t0].[Suffix], [t0].[CompanyName], [t0].[SalesPerson], [t0].[EmailAddress], [t0].[Phone], [t0].[PasswordHash], [t0].[PasswordSalt], [t0].[rowguid], [t0].[ModifiedDate] FROM [SalesLT].[Customer] AS [t0] Query for CustomerQuery_Test_02 (notice the where clause) SELECT [t0].[CustomerID], [t0].[NameStyle], [t0].[Title], [t0].[FirstName], [t0].[MiddleName], [t0].[LastName], [t0].[Suffix], [t0].[CompanyName], [t0].[SalesPerson], [t0].[EmailAddress], [t0].[Phone], [t0].[PasswordHash], [t0].[PasswordSalt], [t0].[rowguid], [t0].[ModifiedDate] FROM [SalesLT].[Customer] AS [t0] WHERE [t0].[CustomerID] = @p0

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  • Validation framework for .NET Compact Framework 3.5.

    - by Michal Drozdowicz
    Do you know of a fast and simple entity validation framework that could be used in a Compact Framework project? I've done some experiments with FluentValidation (using db4o System.Linq.Expressions, but it's rather slow) and EViL (but it seems a bit half-baked). Can you suggest any other or maybe point me to some resources on how to design such a framework so that it's both easy to use and performant?

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  • Union,Except and Intersect operator in Linq

    - by Jalpesh P. Vadgama
    While developing a windows service using Linq-To-SQL i was in need of something that will intersect the two list and return a list with the result. After searching on net i have found three great use full operators in Linq Union,Except and Intersect. Here are explanation of each operator. Union Operator: Union operator will combine elements of both entity and return result as third new entities. Except Operator: Except operator will remove elements of first entities which elements are there in second entities and will return as third new entities. Intersect Operator: As name suggest it will return common elements of both entities and return result as new entities. Let’s take a simple console application as  a example where i have used two string array and applied the three operator one by one and print the result using Console.Writeline. Here is the code for that. C#, using GeSHi 1.0.8.6 using System; using System.Collections.Generic; using System.Linq; using System.Text;     namespace ConsoleApplication1 {     class Program     {         static void Main(string[] args)         {             string[] a = { "a", "b", "c", "d" };             string[] b = { "d","e","f","g"};               var UnResult = a.Union(b);             Console.WriteLine("Union Result");               foreach (string s in UnResult)             {                 Console.WriteLine(s);                          }               var ExResult = a.Except(b);             Console.WriteLine("Except Result");             foreach (string s in ExResult)             {                 Console.WriteLine(s);             }               var InResult = a.Intersect(b);             Console.WriteLine("Intersect Result");             foreach (string s in InResult)             {                 Console.WriteLine(s);             }             Console.ReadLine();                        }          } }   Parsed in 0.022 seconds at 45.54 KB/s Here is the output of console application as Expected. Hope this will help you.. Technorati Tags: Linq,Except,InterSect,Union,C#

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