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PO(Oracle Performance) Will a query based on a view limit the view using the where clause?
 

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  1. PO(Oracle Performance) Will a query based on a view limit the view using the where clause?
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    <p>In Oracle (10g), when I use a View (not Materialized View), does Oracle take into account the where clause when it executes the view?</p> <p>Let's say I have: </p> <pre><code>MY_VIEW = SELECT * FROM PERSON P, ORDERS O WHERE P.P_ID = O.P_ID </code></pre> <p>And I then execute the following:</p> <pre><code>SELECT * FROM MY_VIEW WHERE MY_VIEW.P_ID = '1234' </code></pre> <p>When this executes, does oracle first execute the query for the view and THEN filter it based on my where clause (where MY_VIEW.P_ID = '1234') or does it do this filtering as part of the execution of the view? If it does not do the latter, and P_ID had an index, would I also lose out on the indexing capability since Oracle would be executing my query against the view which doesn't have the index rather than the base table which has the index?</p>
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    1. USPeter Lang
    1. USBestPractices
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    1. COWhen you says index, which one are you talking about 1. P_ID in PERSON 2. P_ID in ORDERS 3. P_ID in MY_VIEW.. I assumed #3 in my answer below and you cannot create index on logical view. You would get ORA-01702 error
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      1. PO(Oracle Performance) Will a query based on a view limit the view using the where clause?
      1. USexiter2000
 

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