On Fri, 2007-03-16 at 20:19 +0100, Kacper Chrapa wrote: > Hi ! > > Is it possible in postgres to define own message for some constraint? > > Example: > If i create check constraint on zip_code column , i want to get > a message: "Zip code is invalid.Please,input code in format: nn-nnn" > and I want to send this message to the end user. > It will be much better(in my case) than "violates constraint > zip_code_check" :-) . > > I can make this validation in trigger (and send msg to application by > notice or raise),but in this case i will duplicate validation > rules (in trigger and in constraint).Effect: Lower performance(i think) > and rules in two places... > There's no custom message for a CHECK constraint violation. You can use an AFTER trigger instead of a CHECK constraint (but that may have a performance impact - test for your application). You can also give descriptive names to your CHECK constraint which may help. It's not a good idea to pass database errors directly back to the user anyway. Regards, Jeff Davis
