I know how to add a typical check constraint where it ensures that the
value matches a short list of codes, etc. I have been searching for the
past few hours to no avail for an example that shows how to add a check
constraint based upon the value in a separate file:
Quick and dirty example would be a state field of two characters that has
to match a predfined table of state abbrev's or a zipcode lookup table...
Does anyone have any examples I can reference? I have been all over the
reference manual and so far haven't found what I'm looking for.