In my project I have one DB used for everything. I want it to break into two databases. Static tables having look up values are to be stored in one DB and another DB would be having tables with dynamic data. My problem is that how would I use foreign key constraint in between those two DBs. Can someone help me out and suggest a way to proceed, better if I'm provided an example for the same.

I thought of using synonyms for tables and then constraints on synonyms. but later I came to know that synonyms couldn't be used for constraints.

I need to maintain relationships among the tables from both DB as the issue is with update, with a new release I just want to update look up tables and for the same I want to split my DB.

I want to know how FileGroups could be used for this.