Hi,

I know how to make a field in a table UNIQUE, but have no clue if it's possible to make 1 field on two (!)tables UNIQUE and how to do this!

For example make sure the are no duplicates in the "login" data (= username) so never ever a client will login and get - by accident - the stuff of the supllier with the same login. Putting everything in one table would be a solution, however my current cms-system can't handle this.

client_id | username | password | more clients stuff...
supplier_id |username | password | more supllier stuff...