How to call DB function from EF LINQ query?

Question

In my database I have define some function, let\'s say it\'s called fnTest. Is it possible to call that function from my LINQ/EF query? Something like this:

Answer 1

Use sql queries for entities. For exaples look on msdn: http://msdn.microsoft.com/en-us/data/jj592907.aspx

Answer 2

First off, fnTest will have to be created as a user-defined function in the database first:

CREATE FUNCTION [fnTest] (@fi int, @f2 int, @param3 int, @param4 int)
RETURNS int
AS ...

Then in your .edmx file, declare the function like this:

<Function Name="fnTest" ReturnType="int" Schema="dbo" >
    <Parameter Name="f1" Mode="In" Type="int" />
    <Parameter Name="f2" Mode="In" Type="int" />
    <Parameter Name="param3" Mode="In" Type="int" />
    <Parameter Name="param4" Mode="In" Type="int" />
</Function>

Now you can bind this function to a method in your model like this:

[EdmFunction("MyNamespace", "fnTest")]
public static int fnTest(int f1, int f2, int param3, int param4)
{
    throw new NotSupportedException("Direct calls are not supported.");
}

You can now use this method in standard LINQ queries.

Further Reading

• How to: Call Custom Database Functions