Oracle Database Discussions

Hi

I am working on a table that has been created with not null check constraints on primary key columns.

I need to prove that not only is this not necessary, but whether the database checks this column twice.

I have created a test table with this issue, inserted a million rows and timed the run, then repeated with the check constraint disabled.

After running a few times, it is consistent that the constraint enabled run is about 70 seconds, as opposed to 60 seconds when disabled.

Although this helps, I don't think this is proof.

I traced the run and tkprof'd the output, but can't find reference to constraint checking in the report.

So, question:

Is there any way I can show for sure if Oracle is double checking the constraint?

Also:

Apart from self documentation, is there any other reason why these not null constraints were applied to PK columns? I can't think of one.......

Many thanks in advance

Chris