I have not used column check constraints before, but I'd like to start using then and so would I'll like to know if there is a direct way to provide feedback to the end user about data validation rules expressed in column check constraints?
For instance, say that I wanted to use a RE to check e-mail address format validity and then the data entry clerk typed in invalid data. My understanding is that when the check constraint returns FALSE, the row will not insert, and an ExecAppend: rejected due to CHECK constraint "table_column " exception is raised. That at least tells the column (albeit in language that would scare the computer-phobe), but I like the exception message to tell the end user what the format is supposed to be. Is my only option to have the end-user application (as opposed to the database) inform the end-user what the correct data format is? If THAT is so, then it seems I might as well also perform the data formatting validation in the application, too, so that at least they'ld both be in the same place and not two separate places. What I'd like is to be able to specify some kind of error message telling the user what the correct format should be, and since the proper format is specified in the database, i.e., in the check constraint, it seems that the proper place to raise an exception providing the remedial instructions would also be in the database. ~Berend Tober ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
