MySQL Workbench: Custom fields for Relationships I have to manage an existing DB, created "manually" without mysql-wb.

I want to draw the printable ER diagram.

When I create a relationship, workbench creates its own external key fields.

How can I create the relationship binding to my own fields?
Are you using the Place a relationship using existing columns option? Using one of the other options will create a new column in the referencing table, which is mostly useful when you're creating new structure.

You can create relationships by editing the table, going to Foreign Keys, and adding it there manually, as well.