Oracle-L: RE: Function based index

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Tue, 09 Apr 2002 12:39:27 -0800
Message-ID: <F001.0043FEB1.20020409123927@fatcity.com>

Rick - No you can't parameterize it because Oracle will actually build an index based on your function. That is a physical index populated with actual data. If the Oracle optimizer was smart enough to handle the parameter, then it would be smart enough to not need the function-based index in the first place. However, you could create multiple function-based indexes to cover several situations. Of course, if you get carried away and create many, complex function-based indexes, then your insert and update performance may suffer.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, April 09, 2002 1:23 PM
To: Multiple recipients of list ORACLE-L

Hi,

If I have a function based index such as CREATE INDEX emp_idx01 on emp(SUBSTR(first_name,1,20))

Is there a way to build index where 1,20 portion can be parameterized? If so how would this be done?

Thanks
Rick

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Author:
INET: Rick_Cale_at_teamhealth.com

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Author: DENNIS WILLIAMS
INET: DWILLIAMS_at_LIFETOUCH.COM

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