Support for Table Valued Functions in EF6 Code First?

Question

Is it possible to call a TVF in EF6 Code First?

I started a new project using EF6 Database first and EF was able to import a TVF into the model and call it just fine. <

Answer 1

[Tested] using:

Install-Package EntityFramework.CodeFirstStoreFunctions

Declare a class for output result:

    public class MyCustomObject
        {
            [Key]
            public int Id { get; set; }
            public int Rank { get; set; }
        }

Create a method in your DbContext class

[DbFunction("MyContextType", "SearchSomething")]
public virtual IQueryable<MyCustomObject> SearchSomething(string keywords)
{
   var keywordsParam = new ObjectParameter("keywords", typeof(string)) 
                           { 
                              Value = keywords 
                            };
    return (this as IObjectContextAdapter).ObjectContext
    .CreateQuery<MyCustomObject>(
     "MyContextType.SearchSomething(@keywords)", keywordsParam);
}

Add

public DbSet<MyCustomObject> SearchResults { get; set; }

to your DbContext class

Add in the overriden OnModelCreating method:

 modelBuilder.Conventions.Add(new FunctionsConvention<MyContextType>("dbo"));

And now you can call/join with a table values function like this:

CREATE FUNCTION SearchSomething
(   
    @keywords nvarchar(4000)
)
RETURNS TABLE 
AS
RETURN 
(SELECT KEY_TBL.RANK AS Rank, Id
FROM MyTable 
LEFT JOIN freetexttable(MyTable , ([MyColumn1],[MyColumn2]), @keywords) AS KEY_TBL      
ON MyTable.Id = KEY_TBL.[KEY]  
WHERE KEY_TBL.RANK > 0   
)
GO

Answer 2

A similar thing is now also provided by the EntityFramework.Functions package. This one seems to be more up-to-date.

The source code is available on GitHub, and the introductory article explains the basic principles.

Answer 3

I actually started looking into it in EF6.1 and have something that is working on nightly builds. Check this and this out.

Answer 4

This is now possible. I created a custom model convention which allows using store functions in CodeFirst in EF6.1. The convention is available on NuGet http://www.nuget.org/packages/EntityFramework.CodeFirstStoreFunctions. Here is the link to the blogpost containing all the details: http://blog.3d-logic.com/2014/04/09/support-for-store-functions-tvfs-and-stored-procs-in-entity-framework-6-1/

Answer 5

I was able to access TVF with the code below. This works in EF6. The model property names have to match the database column names.

List<MyModel> data =
                db.Database.SqlQuery<MyModel>(
                "select * from dbo.my_function(@p1, @p2, @p3)",
                new SqlParameter("@p1", new System.DateTime(2015,1,1)),
                new SqlParameter("@p2", new System.DateTime(2015, 8, 1)),
                new SqlParameter("@p3", 12))
            .ToList();

Answer 6

I have developed a library for this functionality. You can review my article on UserTableFunctionCodeFirst. You can use your function without writing SQL query.

Update

First of all you have to add reference to the above mentioned library and then you have to create parameter class for your function. This class can contain any number and type of parameter

public class TestFunctionParams
    {
        [CodeFunctionAttributes.FunctionOrder(1)]
        [CodeFunctionAttributes.Name("id")]
        [CodeFunctionAttributes.ParameterType(System.Data.SqlDbType.Int)]
        public int Id { get; set; }
    }

Now you have to add following property in your DbContext to call function and map to the property.

[CodeFunctionAttributes.Schema("dbo")] // This is optional as it is set as dbo as default if not provided.
        [CodeFunctionAttributes.Name("ufn_MyFunction")] // Name of function in database.
        [CodeFunctionAttributes.ReturnTypes(typeof(Customer))]
        public TableValueFunction<TestFunctionParams> CustomerFunction { get; set; }

Then you can call your function as below.

using (var db = new DataContext())
            {
                var funcParams = new TestFunctionParams() { Id = 1 };
                var entity = db.CustomerFunction.ExecuteFunction(funcParams).ToList<Customer>();
            }

This will call your user defined function and map to the entity.