> I'd go the other way and use a trigger to validate the data, and roll
> back the transaction if it isn't in valid format (assuming you are using
> transactions). This way, ANY app that puts data in that field gets the
> validation. An error in an application or typing by someone who has
> direct table access will leave you with bunk data, which is worse IMO
> than having to figure out the code for the trigger.
> You have to keep in mind that I generally spend half my day fixing
> broken data though :)
Which is exactly why constraints and this type of stuff needs
to be implemented in the database :-)
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> Mogens Melander wrote:
> > On Thu, May 3, 2007 12:56, Tim Milstead wrote:
> >> Hello,
> >> Is it possible to enforce data formatting in fields using something
> >> a regular expression?
> >> varchar is great but does not stop someone putting in the wrong
> >> reference number.
> >> I suspect the answer is no, you have to do it at a higher level. What
> >> aprroach would people suggest?
> >> Perhaps another table with two fields - field_name and field_regex?
> > And, what would you have mysql do if a user failed to enter fx. valid
> > Maybe you'd be better off, handling input validation in the
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