| Can we create index on view? [message #197331] |
Wed, 11 October 2006 00:12  |
vikasg2006
Messages: 80
Registered: March 2006
Location: Dubai
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hy
Can we create index on view? And is really view make improves the query? If yes then how? One more thing when we create a view is data stored in a view is order by or indexed already if i cannot mention order by clause at the time of view creation (here we suppose that the base table have 2-3 indexes already). Actually today i create one view but still not find any much difference in performance improved?
vikas
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| Re: Can we create index on view? [message #197340 is a reply to message #197331] |
Wed, 11 October 2006 00:33  |
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Maaher
Messages: 7065
Registered: December 2001
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Senior Member |
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Can you create an index on a view?
A view is a stored select statement, not stored data. So, if you want an index you should make it on the base table(s). Note that you can create an index on a materialized view (snapshot).
Is a view sorted by default?
If you don't provide an order by in a view's select statement, the data is not sorted. If Oracle performs an index scan, it might be sorted but there is no guarantee.
Does a view improve performance?
As a view is a stored select statement, it does not guarantee to increase performance. If the SQL is poorly written, the view will not perform very well.
MHE
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