Lets say your index on six columns is on a,b,c,d,e,f. If you use the
column a, you dont need to worry about what kind of index you have
created.
But, if you are using the column 'f', you would need to make sure you
allow reverse scans in your index.
if you use columns b or c or d or e without using a then, i dont think the
composite index will really be effective.
hope it is clear.
thanks,
pavan.


On Wed, October 25, 2006 11:00 am, seshagirirao wrote:
>

> Hi,
>
>
> I have a table with 25 columns and 6 columns are defined as primary key
> and unique rule is 'P'
>
> As per my requirement , I am using one of the primary key coulmns in
> where condition of my select SQL.
>
> Do I need to use all the primary key columns in where condition to
> activate my composit index ? or Will the composit index is activated if
> I use single column ?
>
>
> If I have to use all the coulmns then what is the syntax to use all the
> columns ?
>
>
> My table indexes are below
>
>
> Index Index Unique
> Number of
> schema name rule
> columns -------------- ------------------ --------------
> -------------------------------------------------------
> DMSC XIF1CSA_CALL_AUX_F D 1
> DMSC XIF2CSA_CALL_AUX_F D 1
> DMSC XIF6CSA_CALL_AUX_F D 1
> DMSC XIF7CSA_CALL_AUX_F D 1
> DMSC XPKCSA_CALL_AUX_FA P 6
> DMSC CALL_AUX_FACT_IDX D 1
> DMSC CALL_AUX_FACT_IDX1 D
> 3
>
>
>
>
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