does Entity framework support user defined functions as scalar properties - entity-framework-4

Question

I would like to include the value of a scalar function as a read-only property of an entity, since that I could include that value in a filter, is such a thing possible?

Answer 1

The solution is to add a DefiningQuery like in the following sample:
<!-- SSDL content -->
<EntitySet Name="Emp" EntityType="TestModel.Store.Emp" >
<DefiningQuery>
SELECT EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO, dbo.MyFunc(DEPTNO) AS DNAME FROM EMP
</DefiningQuery>
</EntitySet>
<EntityType Name="Emp">
<Key>
<PropertyRef Name="EMPNO" />
</Key>
<Property Name="EMPNO" Type="int" Nullable="false" />
...
<Property Name="DNAME" Type="varchar" MaxLength ="20" />
</EntityType>
...
<!-- CSDL content -->
...
<EntityType Name="Emp">
<Key>
<PropertyRef Name="EMPNO" />
</Key>
<Property Name="EMPNO" Type="Int32" Nullable="false" />
...
<Property Name="DNAME" Type="String" MaxLength="20" Unicode="false" FixedLength="false" />
</EntityType>
<!-- C-S mapping content -->
...
<ScalarProperty Name="EMPNO" ColumnName="EMPNO" />
...
<ScalarProperty Name="DNAME" ColumnName="DNAME" />
...
The usage example:
using(TestEntities4 db = new TestEntities4()) {
var q = from e in db.Emp where e.DNAME == "RESEARCH" select e;
}

Answer 2

In EF4 you can define a partial class of the same name as your Entity Framework class in the same namespace and add read-only properties to that. I've just done that to expose the description of a connected Entity object as a read-only property of the original object.
namespace same.as.the.data.model
{
public partial class Order
{
public string CustomerName
{
get { return Customer.Name; }
}
}
}