Repeating Drop Down Menus: Preventing Duplicate Selections?

[tatihulot]

Greetings!  A few weeks ago, some of you were kind enough to help me construct a database for my movie collection.  (Thank you, by the way.)

But I just now noticed something.  It’s not really a flaw.  There’s nothing really wrong.  I don’t really HAVE to fix anything.  So, I’m just asking this question out of curiosity.

The database has a few portals with repeating drop down menus.  I just realized I can select the same thing twice. 

For example, if I have the movie Jaws and select Genre, I could select Action/Adventure multiple times. 

Or, I could accidentally select the same actor twice.

Is it possible to tweak the database so that this is prevented?  So if I select Action/Adventure accidentally a second time, the database will prevent this?

Will this require a significant rewrite of the database, or does it require some minor surgery, so to speak?

To repeat, it’s not critical.  I’m just curious about how to prevent this.  Thank you!   Jd

master.fmp12

[comment]

Regarding genres, I doubt you really need a join table or even the Genre table itself. You could probably just use a checkbox field and a custom value list.

With actors, where you do have something useful to record in the Actor table (and possibly in the join table too), you can prevent duplicate entries into the join table by adding a Text field that auto-enters a calculated value =

MovieFK & "|" & ActorFK

and validate this field as Unique.

This will guard against duplicates at the data level. There are additional measures you can take at the layout level to avoid the harsh validation error message. For example, a "dwindling" value list.

 

[tatihulot]

Great.  Thank you once again for your assistance.