I'm using VS 2008 with SP1. I want to use SP in the entity framework. The problem is that my SP returns more than 1 result set. How do I get the multiple result sets? All the online examples are showing single result. Please help me.
Entity Framework unfortunately does not support multiple result sets from stored procedures - not even in the .NET 4 release.
You will need to either rewrite your stored procs, or access them using standard, bare-bones ADO.NET - and ask Microsoft for support for multiple SP result sets in EF 5 !! I'll cast my vote in favor, too!
Related to this question:
Entity Framework - get records in multiple tables using stored procedure
Another SO user reports success with a plugin project, EF Extensions.
As marc_s describes, the feature is not built in to EF... another reason for DBA Developers to shy away from EF, imho.
Related
I'm forced to use a legacy SQL Server 2000 database for an EF-based app I am writing. The tables already exist, so I need to generate the Entities layer. I can do this in VS2010 using MySQL and recent versions of SQL Server, but not 2000.
To get around this, I followed some tutorials that explain how to generate csl, msdl and ssdl files using edmgen.exe.
That works fine. I now have those files in e.g. c:\temp.
Please can someone tell me what to do with these files? I want to Entity Framework-ify a simple console application that I have written. Can I somehow create an 'ADO.NET Entity Data Model' from these files so I end up with what I would have if I had used VS2010 all along?
Thanks
I got it working, here is what I did
1) Use edmgen.exe to generate the files mentioned in my question
"C:\windows\Microsoft.NET\Framework\v4.0.30319\edmgen.exe" /mode:fullgeneration /c:"Data Source=<your_server_here>; Initial Catalog=<your_catalog_here>; UID=<username>;PWD=<password>" /project:<vs2010_project_name> /entitycontainer:<project_name>Entities /namespace:<project_name>Model /language:CSharpEntityFramework
2) Follow these instructions "How To: use your existing CSDL/MSL/SSDL files in the Entity Designer CTP2" - its actually for VS2008 but it worked for me too.
http://blogs.msdn.com/b/dsimmons/archive/2007/12/07/how-to-use-your-existing-csdl-msl-ssdl-files-in-the-entity-designer-ctp2.aspx
3) I had a further problem in that my legacy db had no primary keys so I followed these instructions which also worked
http://pratapreddypilaka.blogspot.in/2012/04/entity-framework-adding-datatable-with.html
These files are referenced in EF's connection string and EF use them at runtime to build a mapping but it can still not work because SQL Server 2000 is not supported by EF (at least EF 4.0 and newer). EF can generate SQL not supported by SQL Server 2000 and you will get exceptions at runtime.
Hey I have a unique and troubling situation.
I am working on a project where my team has used a mixture of Enterprise Data Library plus Entity Framework. Obviously this probably not recommended but it is what I'm stuck with. I would like to take a method written using Enterprise Data Library and also take a different method written using Entity Framework, and wrap both of these methods in a single transaction (without requiring Microsoft Distributed Transaction Service). I'm hoping to minimize rewriting code and be able to wrap the two methods in a single transaction just as they are. Is this possible? Thanks.
Using SQL Server 2008 and .NET 4.0
I suppose you want to mix EF and EntLib queries in the same TransactionScope, without using DTC.
Good news: it's possible. If you use exactly the same connection string for EntLib DAAB and EF DbContext, it will work, depending on the versions of EF, EntLib and SQL Server.
So what you have to do is:
check you have the right versions
get the version of your connection string changed by EF and use it instead of yours.
For 1, I have checked these combinations:
SQL Server must be 2008 or older
EntLib 4.1 + EF 5 doesn't work
EntLib 5 + EF 5 works
For 2, to get the connection string changed by EF you have to debug the execution of code that uses an instance of a DbContext. Set a breakpoint and watch or inspect the DbContext Database.Connection.ConnectionString property. That's the EF version of your connection string. Use it for both EF and EntLib and you'll get rid of DTC.
I have a MVC3 website I have been playing with, and the database is quite well populated. I need to change the underlying models, but of course, the standard approach would drop all data. Having the CREATE SQL (so I can ensure all fields/relationships are in line with the models), and the calculated hash (so EF thinks the models match the database) would allow me to manually make changes to the database.
Is there a way to interrogate a DataContext (or some other object) to:
1. Get the SQL it would use to generate the dataschema; and
2. Get the ERM Metadata hash
I have considered some other migration options, but just want to explore this avenue.
Edit: This is EF4.1, and is running against SQL 2008 R2 if that is of any relevance.
Thanks
Andrew
You can do it with EF Migrations. You'd need to upgrade your project to EF 4.3. You'd use the "Update-Database -Script" ps command.
Here is a link to the ASP.Net team blog on it: http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-code-based-migrations-walkthrough.aspx
Pluralsight also has a course on it. They also have a free trial. http://www.pluralsight-training.net/microsoft/Courses/TableOfContents?courseName=efmigrations
This question is an extension of another question, but I think it warrants its own thread. See See Silverlight Question
I have a stored procedure (SQL 2005) that returns a dynamic data set (different columns/schema) each time it is called.
I want to consume this in Silverlight 3.0 so I need to somehow wire this up using Entity Framework and RIA Services. I also need this to be Bindable (Silverlight Grid) so I need these dynamic columns to be accessible via properties (grid limitation). Any ideas?
In the currently shipping version of the Entity Framework, the only type of stored procedures you can map are those which return entity types. The mapping is done, generally, before you compile, although it seems at least theoretically possible to generate Entity Framework metadata at runtime.
Therefore, I see a few choices.
Give up on the whole idea of consuming a procedure which does not return a defined schema. You will never be able to map such a procedure before you compile.
Dynamically generate EDMX at runtime in order to map an entity type to the expected output columns of the procedure before you invoke. Note that the current version of the Entity Framework is a bit finicky about the columns a procedure returns; you can find documentation about this on MSDN.
In .NET 4.0, there are new features which allow you to inform the Entity Framework about your client schema at runtime without having to generate EDMX first. You might be able to leverage these features in order to map some entity type to the expected output columns of the procedure.
Again, in .NET 4.0, there may be support for procs which return scalar values. I can't remember if this is the case or not.
You can always get a standard database connection from the entity connection and execute the procedure directly, using regular SqlCommands. Unfortunately, this makes your code database-provider-specific, but it may be the simplest solution to your problem. Indeed, using such a procedure at all is already database-server-specific.
You might use a WCF web service wraper for accesing your SP and use the WCF service as data source Brad Abrams has a way to do that on his series of articles on RIA Services
In LINQ2SQL it was possible to set the return type of a stored procedure to auto generated.
I am unable to do so with the Entity Framework.
I want to set the return type of a stored procdure to auto-generated with the Entity Framework.
Is this possible?
Kind regards.
Entity Framework V1 has good support for working with Stored Procedures directly with entities (as Insert/Update/Delete operations) but as you have discovered, out of the box the support for SPs as functions on your ObjectContext is poor. They pretty much always have to map perfectly to an existing entity in your model as the expectation was you would then do changes to the returned results from the SP and hence would want to work with them as entities. Clearly this is not always the case.
Thankfully there are extensions for EF v1 which include improved support for SPs. Download the extensions here.
EF v2 will have better support.