For those of you who use Visio to due your database modeling, you might have run across the slight problem of not being able to get rid of the auto-generated foreign-keys in your tables (assuming you might have deleted and recreated a relation to the same table.)  If you try to generate a database from your model, you’ll find that the foreign keys that you thought you deleted still exist somewhere in ‘limbo’ and as a result, the error checking in Visio goes crazy.

So, how do you get rid of these ‘phantom foreign keys/relationships’?  Well, I found no solutions from Microsoft’s web site, but I did find some work-arounds from a few blog posts.  Here are two methods that seem to work:

Copy Data Structure into a New File

1. Create a new database model diagram
2. Select all of the items in your existing diagram and click Ctrl+C (Copy)
3. Paste the entire diagram into your new diagram.  The “phantom” foreign keys will not be copied.

View (and Delete) Related Tables

1. Right-click on the table with the problem
2. Select "Show related tables" and you should get the "phantom relationship" back
3. Select the relationship and delete it