Question

I have two tables/entities Users and Companies.
Both are linked m-n relationship.
When I use those tables in my EDMX and generate the POCOs, the m-n mapping table disappears (seemingly becasue there is nothing in there except hte two PKs).

Instead, navigation properties get created by the EDMX, which is fine:

user.Companies ... -> gives me all users for that company

and

company.Users ... -> gives me all companies for that user

But what if I wanted all users that do NOT have a company associated with them?
How would I access the missing table to create the proper join?

Answer 1

You should find users without company (as you said), so their use.Companies.Count should be zero, just convert this to linq (like what is below):

var withoutCompanyUsers = Users.Where(x=>x.Companies.Count() == 0).ToList();

Edit: About your second problem: But what if I wanted all copmanies that are not associated with the given user?

In this case you should find companies which doesn’t have specific user:

Checking company has specific user or not:

company.Users.Any(x=>x.ID = givenUserID)

Fetching companies without specific user:

var companies = Companies.Where(x=>!x.Users.Any(y=>y.ID == givenUser.ID)).ToList();