Ok, got a request from a (L)user of the system.
There's a place where you can enter a 'relationship' between users...like spouse, etc. The other person *SHOULD* have an account in the system already. What's desired is when someone enters their unique user name/number (like R184A8), and clicks SAVE, if that user name doesn't exist in the system, it should throw up an error message.
Looks like the fieldname_validate is what I'm after, but don't see how to get that to look in the MySQL table, but just at what's on the screen. Thoughts?