Re: Views - Under the Hood
От | Raymond O'Donnell |
---|---|
Тема | Re: Views - Under the Hood |
Дата | |
Msg-id | 4CD31B8D.7030808@iol.ie обсуждение исходный текст |
Ответ на | Re: Views - Under the Hood (Chris Browne <cbbrowne@acm.org>) |
Список | pgsql-general |
On 04/11/2010 19:58, Chris Browne wrote: > Under the hood, views represent a rewriting of the query. > > http://www.postgresql.org/docs/8.4/static/rules-views.html > > If you have two tables that are joined together, in a view, then when > you query the view, you're really running a more complex query than > you're seeing, namely one that joins together the two tables, and does > whatever else you put into your query. > > It *looks* like a table, for almost all intents and purposes, but what > it is, really, is a structure that leads to your queries being rewritten > to access the *real* tables that underly the view. Besides not being able to write to views without adding extra rules, are there are other intents and purposes for which a view doesn't look like a table? Ray. -- Raymond O'Donnell :: Galway :: Ireland rod@iol.ie
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