When the user enters a new unit, or modifies the current one, I need to save it. But I don't want it to save if the unit is a duplicate. I also want to be the one to give the error message.

Currently, I have a complicated IF to determine if the unit has changed and then I scan through the table to see if it's already there. I also have to make sure I don't get an error if the user changes the unit name, then changes it back, because then it will have changed AND be in the table already.

It seems like there should be a simpler way of doing this. I've made the unit name a candidate index. Can I do the row update and have it tell me if the key's uniqueness was violated?

Is there some way to put this in the database so whenever a user tries to save a duplicate unit, my error message comes up an the save is rejected?

Thanks,

-Michelle