In message <4164e5de$0$10351$afc38c87_at_news.optusnet.com.au>, Howard J.
Rogers <howardjr_at_dizwell.com> writes
>xtanto wrote:
>
>> Hi Gurus,
>>
>> I have Table A with PK on a,b,c,d (so I have index on this)
>> Table A has FK on (a,b) to Table B)
>>
>> Table B with PK on a,b
>>
>> I have questions :
>>
>> (1) On Table A, what queries that can make use of the Index ?
>>
>> (2) On Table A, Do I need Index on (a,b) for the FK
>>
>> Thanks for your help,
>> xtanto
>
>
>This is all a bit abstract, isn't it?
>
>I'm sure someone here is going to ask when you have to have this homework in
>by...
>
>Besides which, although you might not think it, but the advice in respect of
>both questions is influenced by Oracle version. But that said:
>
>1. Any query. In 9i more than in 8i. Read up on skip scanning, for example.
>2. Yes. Even in 9i, if you ever intend to modify table B's primary key.
>
Does the fact that (a,b) is the leading portion of the primary key have
not any effect on this?
--
Jim Smith
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Received on Thu Oct 07 2004 - 03:53:37 CDT
