text: Hero Zzyzzx has asked for the wisdom of the Perl Monks concerning the following question:
  Folks,:Namespace namespace fails 'list' constraint with 'page'.
  The reason I want to catch constraint failures is because I want the constraint checking to act as my HTML form validation check: If the constraint check barfs, I want to re-output the form with an error message on the field that failed. Without an easy way to know which field failed, this won't be easy. Using CDBI constraints to check form values seems like a pretty good way to not repeat myself. . . but I need to give the user specific feedback about the failure.
  Ideas? Thanks in advance.
  * Assuming that perl modules can be cool in the first place. :)