| indexes [message #9386] |
Fri, 07 November 2003 09:52  |
ramu
Messages: 82
Registered: February 2001
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Member |
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How many indexes we can create on single table in oracle 7 database
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| Re: indexes [message #9391 is a reply to message #9386] |
Fri, 07 November 2003 13:28  |
ashish
Messages: 107
Registered: December 2000
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Senior Member |
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dear x,
you can create maximum that no. of indexses
according to the no. of columns of that particular table.
for example:
suppose emp is your table and the maximum no. of indexses that you can create is
no. of indexses=no. of cols of emp
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| Re: indexes [message #9399 is a reply to message #9386] |
Sat, 08 November 2003 07:42 |
Thiru
Messages: 1089
Registered: May 2002
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Senior Member |
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theoretically ,there is no limit per table. You can create indexes on various combinations of the columns involved. In Oracle 7, you can have 16 columns per index and so you can have so many combinations of concatenated indexes,but the total size of the indexed column cannot exceed half the block size(minus some overhead).
Say you have 2 columns .. t( a,b)
you can have indexes on t(a) , t(b) , t(a,b) , t(b,a)
but practically , you may not need the index on t(a), becos you have t(a,b).
-Thiru
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