Question

I am using the VS 2010 Entity Framework designer to modify some of the entities that were auto-generated from a database.

The database structure is defined by a product I am building a UI for so I can’t modify it.

The database has tables that have a many-to-many relationship based purely around common values in non-key columns on both tables.

• Table 1 Users has a single id column userId and another column called userProfile.
• Table 2 SecurityProfile has a single id column securityProfileId and also has column userProfile.

In other words a User Profile is just a name for a mapping of users to SecurityProfiles.

The wizard created entities for both the Users and SecurityProfile tables. I created a new entity called UserProfile with a single key field: userProfile.

I created a one-to-many association from UserProfile to User and from UserProfile to SecurityProfile. This all works fine except that the UserProfile entity has no table mapping so it won’t compile.

How do I create this association in Entity Framework?

UPDATE:

If it’s not possible using EF (as is suggested by the first answer), is it possible to manually create a non-bound entity that I can use to link these two entities so that I expose an object model that is at least a little easier to navigate?

i.e. I would make the User and SecurityProfile entities abstract and manually define an extension of these with the appropriate properties pointing to my manually created UserProfile entity

Answer 1

You will not. EF is not able to work with many to many association which doesn’t exist in database. EF demands same referential integrity as database – in this case it demands junction table to exist and be mapped to association used in diagram.