MV Keys (was: Key attributes with list values)
Date: Sun, 26 Feb 2006 11:43:00 +0100
Message-ID: <440185c0$0$11076$e4fe514c_at_news.xs4all.nl>
dawn wrote:
> ... What does it mean that a list is a key? If
> I change one value in the list, does that make it a new key? I would
> think so.
If I change the order of the items in the list, does that make it a new key? I would think so. (See below)
> It might model a proposition something like
>
> The team with people whose ID's are 112233 and 123456 has a best run of
> 38 seconds in the potato sack race.
The team with people whose ID's are 123456 and 112233 has a best run of 38 seconds in the potato sack race.
Would be the same proposition, right?
So, in this example we have a set-key, not a list-key.
> Most data modelers would choose to provide a team identifier rather
> than implement a multivalued ID (even MV developers).
Received on Sun Feb 26 2006 - 11:43:00 CET