Re: CTAS only recreate non-NULL contrainsts - WHY?
Date: Mon, 24 Mar 2008 22:40:33 -0700 (PDT)
Well, think about it.
If I do a CTAS which is a join between two tables, then which primary key gets moved over? You can define the primary key in the CTAS command if you need to like this:
create table newemp (empid primary key) as select empid from emp;
With respect to FK's, the same logic applies.... you could be creating rows that would violate the existing FK (say with an outer join).
Robert G. Freeman
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Blog: http://robertgfreeman.blogspot.com (Oracle Press)
- Original Message ---- From: Peter Teoh <htmldeveloper_at_gmail.com> To: Oracle-L Freelists <oracle-l_at_freelists.org> Sent: Monday, March 24, 2008 10:33:26 PM Subject: CTAS only recreate non-NULL contrainsts - WHY?
It is known that CTAS only recreate the constraints if it is non-NULL, while others like primary key, foreign keys are all not created.
Is there any reason why?
http://www.freelists.org/webpage/oracle-l Received on Tue Mar 25 2008 - 00:40:33 CDT