Re: SQL Statement Help Needed
От | Charley Tiggs |
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Тема | Re: SQL Statement Help Needed |
Дата | |
Msg-id | 1EF00931-07B8-4551-AA6D-8124194157AA@xpressdocs.com обсуждение исходный текст |
Ответ на | Re: SQL Statement Help Needed (<me@alternize.com>) |
Список | pgsql-novice |
On Dec 5, 2005, at 10:44 PM, <me@alternize.com> <me@alternize.com> wrote: > correct me if i'm wrong, but i don't think having a completely > normalized datastructure makes always sense. if one would need to > query an employee and having all phone numbers & stuff in one > single view, you'll end up having a huge amount of joins. this is > bound to "cost" performance while the "win" (diskspace) is > relatively small. Actually, it depends on what you're after in the long run. De- normalizing phone numbers might make sense if all you really need is the current contact information for a particular user. But if you really need a history of sorts of the contact information associated with a user, normalization makes all the sense in the world. As well, you can't really predict how your information needs will evolve. You can make educated guesses but you really can't say, "We'll never need that." As always, make a decision based on your particular situation and what your needs are. It also doesn't hurt to plan a little for things that may never happen but could. The more you do so, the less traumatic it will be to change later. Charley
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