ADO.NET Entity Framework Extensions

NEW POST: EF 4.0 support

yashgt — Mon, 09 Nov 2009 04:31:45 GMT

Hi,

Will the features of EF extensions be part of EF 4.0 or will it be a separate DLL that works with EF 4.0?

Thanks,
Yash

NEW POST: Entity framework access through ODBC

VenkateshSrini — Wed, 02 Sep 2009 14:13:32 GMT

Hi,

Can any one let me know what needs to be done to use ADO.NET entity framework using ODBC ?

Thanks in advance
Venkatesh

NEW POST: Using Materializer with dynamic field set

Kinnar — Tue, 18 Aug 2009 07:39:01 GMT

I have the same requirement as parheric as descirbed above. I want to use same materializer for all the result sets returned for particular entity.
Some result sets may contain certain columns and other result sets may not contain it. But want to use same materializer for all the result sets instead of
creating new materializer per result set.

Please provide your feedback on above this.

NEW POST: Error Materializing Inherited Classes

dalehirt — Tue, 18 Aug 2009 01:00:48 GMT

As an FYI, I finally figured out the issue. Expression.Bind fails miserably when it is passed a MethodInfo that is from a subclass.

The fix is to pass it a MemberInfo instead and this doesn't worry about subclassing at all.

Change line 218 in Materializer.cs from:

memberBinding = Expression.Bind(propertyInfo.GetSetMethod(), CreateGetValueCall(propertyInfo.PropertyType, columnName, ordinal));

to:

memberBinding = Expression.Bind(propertyInfo, CreateGetValueCall(propertyInfo.PropertyType, columnName, ordinal));

NEW POST: Error Materializing Inherited Classes

dalehirt — Mon, 17 Aug 2009 20:50:14 GMT

I am using the Materialize function to map 3 different stored procs into lists.

1. Maps a stored proc directly to an EF object. Yippee it works.

2. Maps a stored proc directly to a custom object. Yippee it works.

3. Maps a stored proc directly to a custom object that inherits from an EF object. FAILS!!!!

I receive this error when I do:

System.ArgumentException was unhandled by user code
Message="The method 'DDBackup.Components.Data.BackupRequests.set_BackupRequestId' is not a property accessor"
Source="System.Core"
StackTrace:
at System.Linq.Expressions.Expression.GetProperty(MethodInfo mi)
at System.Linq.Expressions.Expression.Bind(MethodInfo propertyAccessor, Expression expression)
at Microsoft.Data.Extensions.Materializer`1.TryCreateMemberBinding(String columnName, Nullable`1 ordinal, MemberBinding& memberBinding) in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\EFExtensions\Materializer.cs:line 218
at Microsoft.Data.Extensions.Materializer`1.GetDefaultShaper(ReadOnlyCollection`1 fieldNames) in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\EFExtensions\Materializer.cs:line 172
at Microsoft.Data.Extensions.Materializer`1.InitializeShaper(IDataRecord record) in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\EFExtensions\Materializer.cs:line 134
at Microsoft.Data.Extensions.Materializer`1.<Materialize>d__a.MoveNext() in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\EFExtensions\Materializer.cs:line 106
at Microsoft.Data.Extensions.Materializer`1.<Materialize>d__0.MoveNext() in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\EFExtensions\Materializer.cs:line 88
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToListTSource(IEnumerable`1 source)
at DDBackup.Components.Model.DDBackupRepository.GetRequestsByStatus(Int32 Id) in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\DDBackup.Components\Model\DDBackupRepository.cs:line 142
at DDBackup.Models.Views.AdminRequestsViewModel..ctor(RequestStatus status) in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\DDBackup\Models\Views\AdminRequestsViewModel.cs:line 19
at DDBackup.Controllers.AdminController.Requests(String id) in C:\Users\dalehirt\Documents\DDIT\Dev\Tools\DDBackup\DDBackup\Controllers\AdminController.cs:line 25
at lambda_method(ExecutionScope , ControllerBase , Object[] )
at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters)
at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.<>c_DisplayClassa.<InvokeActionMethodWithFilters>b_7()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
InnerException:

The property that it is failing on is a member of the EF object. So I'm not sure why it would fail there.

Any and all help is appreciated. I love the EF Extensions and I do hope they make part of their way into EFv4.

Dale

NEW POST: Access to the default shaper

AnatoliM — Wed, 08 Jul 2009 17:04:45 GMT

First of all, many thanks for developing these entity framework extensions. Not only are they very useful, but I've learned a lot about the EF while playing with your code too.

If I understand it correctly, in the Materializer class one can either use the default object shaper, or supply a custom shaper. This is fine, but a little limiting, because in many cases default shaper functionality is almost adequate, but requires just a bit of custom adjustments. For instance, I ran into a situation where I wanted to set EntityKey on a detail entity to point to its master record, but I could find no way to do it other than to provide a completely custom shaper, which is inconvenient considering that the entity had some 50 properties and the default shaper was doing such a good job populating them automatically.

So my suggestion is either (1) to provide public access to the default shaper, making it possible to define a custom shaper, which would in turn invoke the default shaper to do the bulk of the work, or (2) to augment the Materialize method calls with post-shaper callback handlers, passing DbDataReader and the newly created entity as parameters. The first approach is probably more flexible.

NEW POST: SPROC with Out-parameter

EDVGradl — Thu, 02 Jul 2009 12:04:47 GMT

Hi!
I am beginning to use EFExtensions, because i need to call SPROCs in my database. All is fine, but i have many SPROC with OUT parameters. Wenn i call a SPROC with EFExtensions i get an exception like this:
Procedure or function 'aSPROC' expects parameter '@aOutParam', which was not supplied. But this parameter is an out-parameter. When i supply this parameter i get nothing returned :-(
How can I achieve this problem?

Thanks!

NEW POST: Using Materializer with dynamic field set

parheric — Mon, 29 Jun 2009 15:33:40 GMT

Was hoping to get some guidance for using materializers with dynamic fields returned.

Calling a proc that returns search results, but depending on the search options, certain columns may/may not be returned in the results set.
Is there a preferred method to populate an entity using a func<t1,t2> without having to create a different materializer for each 'shaped' result set?

the only 'neat' way that I've found to do this is too pass a idatareader into the constructor of the entity, however I still haven't found a way to detect if a field actually exists in the result set.

UPDATED RELEASE: EF Extensions Visual Studio 2008 SP1 (Aug 12, 2008)

Fri, 22 May 2009 19:27:20 GMT

This updated version of the extensions library targets the Visual Studio 2008 SP1. Changes include:

* Helpers simplifying getting and setting key values for EntityReferences.

2009-22-5 update:

* Sample project now available in VB

2008-12-7 update:

* Bug fix: using *ObjectContext.CommandTimeout* in calls to *CreateCommand*.
* Sample project now illustrates use of *EntityReference* properties when materializing results.
* New helper method overloads have been added to support *InvocationExpression* in LINQ queries and expressions.

UPDATED RELEASE: EF Extensions Visual Studio 2008 SP1 (Aug 12, 2008)

Fri, 22 May 2009 19:26:12 GMT

This updated version of the extensions library targets the Visual Studio 2008 SP1. Changes include:

* Helpers simplifying getting and setting key values for EntityReferences.

2008-12-7 update:

* Bug fix: using *ObjectContext.CommandTimeout* in calls to *CreateCommand*.
* Sample project now illustrates use of *EntityReference* properties when materializing results.
* New helper method overloads have been added to support *InvocationExpression* in LINQ queries and expressions.

NEW POST: How do I install the extension?

EAlmeida — Thu, 26 Feb 2009 16:49:44 GMT

Sorry, but I don't find how do I install the extension.
Thanks for any help :)

NEW POST: can't get sample to run

balq60 — Thu, 12 Feb 2009 20:15:52 GMT

I run the darn thing and there are NO parameters setup to pass in when you run this.

I know it's looking for the connectgion string, so I added that as a parameter, but still no luck.

It would be nice, if for once, when I download an example from Microsoft, it would work...

NEW POST: DefaultShaper with EntityKey for

emikelsoft — Tue, 03 Feb 2009 21:34:21 GMT

Is it possible to extend the DefaultShaper to include the entitykeys of all relations of an entity?

thx, emikelsoft

UPDATED WIKI: Home

cmeek — Sun, 07 Dec 2008 17:22:50 GMT

The ADO.NET Entity Framework Extensions library includes utilities that make querying stored procedures, creating typed results from DB data readers and state tracking external data much easier in the Entity Framework. A sample application demonstrates several patterns using these utilities, including stored procedures with multiple result sets, materialization of CLR types, and registering entities in the Entity Framework state manager.

Overview

Utilities are included to simplify:

Execution of store commands via the ObjectContext.
Connection lifetime management.
State management of entities from external sources.
Materialization of arbitrary CLR types given a data reader or DB command.
Stored procedure mapping:

Multiple result sets.
Column renames, polymorphic results and nested structures via the materialization service.

Getting and setting key values for entity references.
Rewrite InvocationExpressions in LINQ queries and expressions.

Requirements

Visual Studio 2008 SP1.

http://msdn.microsoft.com/en-us/vsts2008/products/cc533447.aspx

Other resources

The following post introduces the EFExtensions API and includes a walkthrough of the sample application:

http://blogs.msdn.com/meek/archive/2008/03/26/ado-entity-framework-stored-procedure-customization.aspx

For additional information on multiple result sets and relationships, see:

http://blogs.msdn.com/meek/archive/2008/12/07/stored-procedures-and-first-class-relationships-in-the-entity-framework.aspx

For additional information on InvocationExpression rewriting, see:

http://blogs.msdn.com/meek/archive/2008/12/07/invocationexpression-and-linq-to-entities.aspx

UPDATED RELEASE: EF Extensions Visual Studio 2008 SP1 (Aug 12, 2008)

Sun, 07 Dec 2008 16:43:37 GMT

This updated version of the extensions library targets the Visual Studio 2008 SP1. Changes include:

* Helpers simplifying getting and setting key values for EntityReferences.

2008-12-7 update:

* Bug fix: using *ObjectContext.CommandTimeout* in calls to *CreateCommand*.
* Sample project now illustrates use of *EntityReference* properties when materializing results.
* New helper method overloads have been added to support *InvocationExpression* in LINQ queries and expressions.

UPDATED RELEASE: EF Extensions Visual Studio 2008 SP1 (Aug 12, 2008)

Sun, 07 Dec 2008 16:41:38 GMT

This updated version of the extensions library targets the Visual Studio 2008 SP1. Changes include:

* Helpers simplifying getting and setting key values for EntityReferences.

2008-12-7 update:

* Bug fix: using *ObjectContext.CommandTimeout* in calls to *CreateCommand*.
* Sample project now illustrates use of *EntityReference* properties when materializing results.
* New helper method overloads have been added to support *InvocationExpression* in LINQ queries and expressions.

NEW POST: EFExtensions does not work well with VB.NET

PJonDevelopment — Wed, 26 Nov 2008 20:13:33 GMT

Never mind my previous post, I forgot to add the Microsoft.Data.Extensions namespace as an Import.

Paulo Santos
http://pjondevelopment.50webs.com

NEW POST: EFExtensions does not work well with VB.NET

PJonDevelopment — Wed, 26 Nov 2008 18:38:17 GMT

Hi,

The EFExtensions does not work as extension methods when used with VB.NET.

All the static methods needed to be called as they are and not as extensions as they should.

Regards,

Paulo Santos
http://pjondevelopment.50webs.com

NEW POST: Does the EF model requires the Data Objects to be mapped to a table?

Pranav — Thu, 21 Aug 2008 23:39:05 GMT

There is a feature called ModificationFunctions which allow you would use your own stored procs that map to InsertFunction, DeleteFunction and UpdateFunction. This way your entities are still mapped to the tables but the logic to do any CRUD operations is overridden by your sprocs.

Here is an example I have from my edmx file:
[EFMappingFileSamples > ModificationFunctions
In SSDL:
<Schema Namespace="exp.Store" Alias="Self" ...
...
<Function Name="usp_CreateExperiment" Aggregate="false" BuiltIn="false" NiladicFunction="false" IsComposable="false" ParameterTypeSemantics="AllowImplicitConversion" Schema="dbo">
<Parameter Name=“experiment_id” Type="varchar" Mode="In" />
<Parameter Name="description" Type="varchar" Mode="In" />
</Function>
<Function Name="usp_UpdateExperiment" …
<Function Name="usp_DeleteExperiment" …

In MSL:
<EntitySetMapping Name="Experiments">
<EntityTypeMapping TypeName="exp.Experiment">
...
<ModificationFunctionMapping>
<InsertFunction FunctionName="exp.Store.usp_CreateExperiment">
<ScalarProperty Name=“experimentid” ParameterName=“experimentid” />
<ScalarProperty Name="description" ParameterName="description" />
<AssociationEnd AssociationSet="FKcontroltreatment" From="Experiment" To="Treatment">
<ScalarProperty Name=“experimentid” ParameterName=“experimentid” />
</AssociationEnd>
</InsertFunction>
<DeleteFunction …
<UpdateFunction …
</ModificationFunctionMapping>
<AssociationSetMapping Name=" FKcontroltreatment" TypeName="exp.FKexperimentscontrol_treatment" StoreEntitySet="experiments">
<EndProperty Name="treatments">
<ScalarProperty Name="treatmentid" ColumnName="controltreatment" />
</EndProperty>
<EndProperty Name="Experiment">
<ScalarProperty Name="experimentid" ColumnName="experimentid" />
</EndProperty>
<Condition ColumnName="control_treatment" IsNull="false" />
<ModificationFunctionMapping>
<InsertFunction FunctionName="exp.Store.uspCreateExperimentJunk">
<EndProperty Name="Experiment">
<ScalarProperty Name="experimentid" ParameterName="experimentid"/>
</EndProperty>
<EndProperty Name="Treatment">
<ScalarProperty Name="treatmentid" ParameterName="treatmentid"/>
</EndProperty>
</InsertFunction>
<DeleteFunction….
</ModificationFunctionMapping>
</AssociationSetMapping>

Note:
1. If one modification function mapping is created for an entity all the 3 should be created i.e InsertFunction, DeleteFunction, UpdateFunction. Also any associations related to this entity should also have modification functions for InsertFunction and DeleteFunction.
2. StoredProcs for InsertFunction, DeleteFunction and UpdateFunction cannot be exact same. But it is possible to put a dummy stored proc that does not exist in database as long as that function is not invoked.

UPDATED WIKI: Home

cmeek — Tue, 12 Aug 2008 19:54:35 GMT

Overview

Utilities are included to simplify:

Execution of store commands via the ObjectContext.
Connection lifetime management.
State management of entities from external sources.
Materialization of arbitrary CLR types given a data reader or DB command.
Stored procedure mapping:

Multiple result sets.
Column renames, polymorphic results and nested structures via the materialization service.

Getting and setting key values for entity references.

Requirements

Visual Studio 2008 SP1.

http://msdn.microsoft.com/en-us/vsts2008/products/cc533447.aspx