One From Column A, One From Column B

[billroper]

The problem with decoupling your UI code from your Server code is that you can manage to write two different validations for data entry with two different sets of rules. This is, perhaps, not a good thing.

Comments

[tigertoy]

I can't tell the details of this situation, but in general terms looking at your data twice seems like a good thing. If it passes both tests, written from different viewpoints, it's more likely to be good. It never hurts to check twice.