Primary Constraints and Indexes

From: Wayne McGill <McGillWL_at_navair.navy.mil>
Date: Wed, 10 Jan 2001 07:43:09 -0800
Message-Id: <10737.126273@fatcity.com>

As a part-time dba, I am confused about the differences between Primary Keys and Indexes.

For example if I create a table "EMPLOYEES" and in the table creation statement I do something like:

     create table ...
        constraint XXX primary key (EMP_ID) using index ...

then later I create an index:

   create index YYY on EMPLOYEE (EMP_ID) ... I know I have created two indexes (the first one system-named and implicitly created and the second name YYY and created explicitly) but do I really need the second index YYY? It seems to me the YYY index is not really needed? Can someone shed some light on this for me.

THANKS, Wayne
McGillWL_at_navair.navy.mil Received on Wed Jan 10 2001 - 09:43:09 CST