On Nov 23, 2006, at 10:23 AM, Ron Johnson wrote:
I'm one of those who thinks that a (possibly multisegment) natural key *does* exist, and that if you think it doesn't, your design is wrong.
I agree, but that doesn't mean you want to be spreading that multi- field key throughout your database. For example, origination, destination, flight_number, and date together make a unique key for a segment of a flight. But that doesn't mean you want to be storing all that info in every other table in the database that references a segment. Not only does moving all that data around become non- trivial, writing all that stuff into all the joins is error-prone (not to mention a PITA).
-- Jim Nasby jim@xxxxxxxxx EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
