Re: Database Structure Question - Keys

On Jul 16, 8:54 am, "faceman28..._at_yahoo.com" <faceman28..._at_yahoo.com> wrote:
> Supposed I have a database table of millions of transaction records.
> In nearly every case, I need to access the records by customer ID and
> date. So nearly all queries will look something like
>
> SELECT ........ WHERE CUSTOMER_ID=x AND TRANSACTION_DATE=y ......
>
> The number of customers is realatively small compared to the number of
> database records (+/-50).
>
> So a
>
> SELECT .... WHERE CUSTOMER_ID=X
>
> could return millions of records.
>
> SELECT .... WHERE TRANSACTION_DATE=y
>
> could return a few million records.
>
> SELECT ........ WHERE CUSTOMER_ID=x AND TRANSACTION_DATE=y ......
>
> would return tens to hundreds of thousand records.
>
> QUESTION: In such a situation on Oracle, is one better off defining
> two keys on CUSTOMER_ID and TRANACTION_DATE or is it better to have
> one compound key consisting of both columns?

Also see http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/optimops.htm#sthref1298

jg

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