Re: dual table - 9iR2

Oradba Linux wrote:

> I am curious about the behavior of dual table in oracle 9iR2 . It looks
> like when selecting from dual, implicitly where rownum=1 is added .
> I am just curious about how it works .

DUAL is a table provided to give you exactly one row and one column.

Mucking with the contents can be dangerous to the health of your database and many applications written for Oracle. As a matter of fact, it's so important it's owned by the one userid, SYS, that should only be used in extreme cases such as startup, shutdown and emergency maintenance.

In answer to your implied question 'What is ROWNUM?' ... it is a pseudo-column generated by the RDBMS engine at run time.

Since this is explained in the Concepts manual at http://docs.oracle.com, I can only conclude you have not had a chance to read that ... sad Received on Tue Sep 14 2004 - 21:40:44 CDT