Using two different databases simultaneously using Entity Framework

Question

I'm using Entity Framework 4 in an MVC3 project. I'm trying to access two different databases (A and B):

• Databases A and B are completely different and unrelated.
• Database A is a 'code first' SQL compact database.
• Database B is a 'database first' SQL Server database.
• I have straightforward queries on either database, no linking or cross-database joins.
• Either database connection works if I remove the other DbContext from the project.

Now, when I try to query from database A, I'm getting an Exception "Could not find the conceptual model type for ".

I can't imagine that EF doesn't let you use different databases, so my question is: do I need to do something extra when creating a new instance of the appropriate DbContext, in order for this to work?

Answer 1

I stumbled across this thread while trying to resolve the "Could not find the conceptual model type for" exception.
I am using EF 4.2 with multiple models. I implemented DbContext with one of my models to "try it out". When I compiled and ran, I received the exception above for an entity in a completely different model on a completely different database!

After much hassle I finally implemented DbContext to the other two models and everything ran fine.

I know this doesn't necessarily answer the question, but I wanted to leave this here for anyone else that has the same issue and stumbles across this post.

Answer 2

Make sure you don't use the same entities name for both edmx files. You can change it manully opening a edmx with xml editor right clicking the file and open with.

Note that for some security reasons you can't nest the contexts. They can only be used separated.