In the last episode (Aug 26), Karl Larsen said: > I was working with my version 5 and made a couple of views which > are very useful. Looking in the db I was able to see the VIEW's saved > as TABLE :-)
What command did you run to determine this? "SHOW TABLES" does list them but that's to be expected since views act like tables. "SHOW TABLE STATUS" and selecting from information_schema.tables both clearly distinguish tables from views. > This was a surprise and not sure if this is the expected result or > not. Then I did some SELECT that involved the VIEW and it does work a > lot like another TABLE, but it can and mine does take data from many > TABLE's into a VIEW. > > You can write a SELECT or even another VIEW using a VIEW. But if > you keep track of the time used by a query, it starts to get too long > if you use a SELECT of a VIEW that has within it another VIEW. Mysql's optimization of views is currently very rudimentary. If your view is simple (adding a computed column, etc) it directly modifies your query to match the view and runs it on the view's parent table. Otherwise it has to create a temporary table containing the entire view's contents and then run your query on that. Nested views using temptables could certainly be very slow. http://dev.mysql.com/doc/refman/5.0/en/create-view.html http://dev.mysql.com/doc/refman/5.0/en/view-restrictions.html -- Dan Nelson [EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
