Good questions. Please correct me if I'm wrong, but isn't a join
dependency when you are able to join decomposed tables on common keys
to get the original table? In my case, I thought I had found a join
dependency because most of the time, if I joined the decomposed tables
together I got the original back. But every so often a spurious tuple
showed up. Would this be an example of checking if a JD held? (and it
didn't hold when the spurious tuple showed up)? Is the only way to
check this by trial-and-error?
So if there would have been no spurious results, then I assume the JD
would have held and thus I should have decomposed. I'm just not sure
why my data set didn't have the JD when I have seen similar sets of
data (with three inter-dependant columns) that did have JD's. Are all
JD's cyclic? Thanks, I appreciate the explanations.
Received on Thu Jun 16 2005 - 14:39:37 CDT
