Entity Framework - How do I join tables on non-primary key columns in secondary tables?

Question

I want to join 2 tables using entity framework. I want the join to the second table to be on a non-primary key column.

e.g. I have a table Foo with fields

Foo.Id (PK)
Foo.DbValue

and table Bar

Bar.Id (PK)
Bar.DbValue
Bar.Description

And I want to join Foo to Bar in EF on the DbValue field.

In hibernate/nhibernate one can do this by adding a column parameter to a many-to-one. roughly like this

<class name="Foo" table="Foo>
  <id name="Id" column="Id" />
  <many-to-one name="Bar" class="Bar" column="**DbValue**" />
</class>

Thanks in advance if anyone knows how to do this in EF. Mark

Answer 1

Well you can't do this as a named relationship (i.e. the standard way).

So this means the relationship is NOT part of the model.

However you can still do a standard LINQ join though:

from f in ctx.Foo
join b in ctx.Bar on f.DbValue equals b.DbValue
select new {f,b} 

Hope this helps

Alex James

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