Re: Unable to use VIEWS (Ok button remains shaded)
От | Mladen Gogala |
---|---|
Тема | Re: Unable to use VIEWS (Ok button remains shaded) |
Дата | |
Msg-id | 4C9386FA.5060407@vmsinfo.com обсуждение исходный текст |
Ответ на | Re: Unable to use VIEWS (Ok button remains shaded) (Josh Kupershmidt <schmiddy@gmail.com>) |
Список | pgsql-novice |
Josh Kupershmidt wrote: > On Thu, Sep 16, 2010 at 10:00 PM, Mladen Gogala > <mladen.gogala@vmsinfo.com> wrote: > >> I always wandered why would anybody want to update a view? View is, by >> definition, a stored query which is executed frequently enough to be given >> its own first name, middle name and a family name. If the view is being >> updated, the middle name is F, just as in the case of Bucky Dent. I don't >> see any database design pattern which would necessitate updating a view. >> That is a perversion, not unlike putting ketchup on a hot dog. >> > > See C.J. Date's "SQL and Relational Theory", a good read. Page 195, > "SQL and Views: Update Operations" talks about this. Quote: > > That is all good and well. My objection wasn't to the relational theory and the principle of interchangeability, it was to a bad practice. As a DBA since 1989., I've never had a need for updating a view, except when simulating "update from". That's all I've said. Furthermore, my experience tells me that updating views usually leads to under-performing applications. The same applies to the philosophy which puts optimizer hints at the "unwanted" list. Hints are bad in theory, but unless optimizer can always make a good decision, there should be a way of influencing the optimizer decisions. -- Mladen Gogala Sr. Oracle DBA 1500 Broadway New York, NY 10036 (212) 329-5251 http://www.vmsinfo.com The Leader in Integrated Media Intelligence Solutions
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