Allow ONLY duplicates in two fields

[KWasley]

Hello,

I have created a database which holds architectural drawings for my company. The drawings have a number (dwgNumber), a name (dwgTitle) and a revision (dwgRevision). Each number should only have one title but cannot be unique as they can have several revisions. I am looking for a way to allow the users of the database to only enter a drawing title for a drawing number once. This is because if more than one person is accessing the front end at a time, they may use the same drawing number for different drawings.

For Example:



----THIS IS FINE
Number: A001 Title: Drawing 1 Revision: P1
Number: A001 Title: Drawing 1 Revision: P2


----THIS IS NOT OK
Number: A001 Title: Drawing 1 Revision: P1
Number: A001 Title: Drawing 2 Revision: C1


I hope this makes sense. Basically, each number can only have one title assigned to it. Does anyone know a way to do this?

Many Thanks in advance,
Kyle

[KWasley]

OR

preferably, would there be a way to lock the front end off to whoever is currently using it to avoid this conflict in the first place?

For example if user 1 tries opening the front end whilst user 2 has it open, access is denied.

Thanks,
Kyle