Include while joining

Question

Hi,

I have a query like this

using (AIR20_con context = new AIR20_con())
{
        var result = from s in context.StudentSet.Include("Nat")
                          join v in context.VInsSet on s.RELATIE_ID equals v.RELATIE_ID
                           where (s.NAT.NATGBA != 1 && v.INS_JR == insJr)
                           select s;

Do have a relationship, while VIns and Student have the same column (Relatie_id).

In the result the table NAT is not included, while query like

using (AIR20_con context = new AIR20_con())
            {
                var result = from s in context.StudentSet.Include("Nat")
                             where (s.Field != 1)
                             select s;

has no problem.

Can I solve the problem, or should I create a work around? By the way, its an Oracle DB with DevArt dataprovider

Robin

Answer 1

Hi Robin

This behavior is by design.

If the query contains operation that changes the intermediate result type between the Include and the outer most operation, like the join operation does in your first query, the Include is ignored.

You could rewrite the query in the following way to have to Include honored:

var result = ((ObjectQuery<Student>)(

               from s in context.StudentSet.Include("Nat")

              join v in context.VInsSet on s.RELATIE_ID equals v.RELATIE_ID

              where (s.NAT.NATGBA != 1 && v.INS_JR == insJr)

              select s).Include(“Nat”);

I hope that helps.

Thanks,

Kati

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Answer 2

Thanks Kati,

This solves the problem

Robin