mysql - How to Maintain Foreign Key Constraint Across Different Databases?

Question

I know, I know, putting two related tables on different databases isn't exactly the best design practice. But for whatever's sake, suppose that I have to do it absolutely. And I have to break up two foreign-key-related tables that were previously located in a database into two databases, that are located on two different servers, but I still want to maintain the database(s) integrity. What is the best way to do this?

Edit: I am using MySQL and Symfony

Answer 1

Have you considered Federated tables? These are basically links to tables which are hosted on a different databases on a different/same host.

You can create a federated table locally and use that to enforce referential integrity. However, I cannot overemphasize the fact that this approach is fraught with future gotchas and not at all recommended.