On Thu, 2004-08-19 at 17:21, Josh Berkus wrote: > Jan, > > > Because the value in b.y is redundant. b.x->a.x->a.y is exactly the same > > value and he even wants to ensure this with the constraint. > > And in the absence of that constraint, what ensures that b.y = a.y, exactly?
In the absence of b.y, it would be impossible for it to be anything else. Isn't that the point? It seems to me that he was trying to use the database to show errors in his source data, but since his constraint would reject the data, he wouldn't be able to enter it; all he could do would be to see the error. So he might as well turn it round, normalise the data properly and use the database to tell the rest of the system what the data ought to be. Oliver Elphick ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly