| function index Vs IOT [message #61085] |
Sun, 28 March 2004 03:25  |
ashokmote
Messages: 56
Registered: December 2003
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Member |
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can any one explain about function index.when we have to use. what the advantages and disadvantage
and also
about IOT, when we have to use IOT,what the advantages and also disadvantages,how the storage takes place.
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| Re: function index Vs IOT [message #61101 is a reply to message #61085] |
Mon, 29 March 2004 21:34  |
dilip kumar
Messages: 111
Registered: December 2003
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Senior Member |
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hi
A function based index as we now that we can write only in oracle database from 8i version and a user should have query rewrite system privilege
if you have table data on which u have written many applications(like procedures/functions) and if we access the data frequently with the help of select statement with where clause and in where clause if u use any single row functions like
select * from emp where ename=upper(ename)
and this type statement if ur frequently using on the tables then u can avoid the FTS by creating the function based on the upper function.
And iot tables are useful if u want sort the data based on primary key column of a table it will store the data in ascending order according to user insertion/updation and there is another advantage as iot the table itself will store in index then when ever u update the primary key column of iot then this updatation is much faster then updation on normal table indexes.b.cos updation has to occur only on index of iot.
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