Re: ON DELETE NULL

A copy of this was sent to Doug Cowles <dcowles_at_nospambigfoot.com> (if that email address didn't require changing) On Thu, 09 Dec 1999 01:15:07 -0500, you wrote:

>Can anyone explain to me why Oracle has no "on delete null" delete
>rule?
>DB/2 has it. It seems to me it wouldn't be too much trouble for Oracle
>to
>put it in since they already have "on delete cascade". Does it
>contradict
>their database philosophy?
>
>- Dc.

It is in Oracle8i, release 8.1:

tkyte_at_8i> create table p ( x int primary key );

Table created.

tkyte_at_8i> create table c ( y int primary key, x int references p(x) on delete set null );

Table created.

tkyte_at_8i>
tkyte_at_8i> insert into p values ( 1 );

1 row created.

tkyte_at_8i> insert into c values ( 1, 1 );

1 row created.

tkyte_at_8i>
tkyte_at_8i> delete from p;

1 row deleted.

tkyte_at_8i> select * from c;

         Y X
---------- ----------

         1

--
See http://osi.oracle.com/~tkyte/ for my columns 'Digging-in to Oracle8i'... Current article is "Part I of V, Autonomous Transactions" updated June 21'st  

Thomas Kyte                   tkyte_at_us.oracle.com
Oracle Service Industries     Reston, VA   USA

Opinions are mine and do not necessarily reflect those of Oracle Corporation Received on Thu Dec 09 1999 - 10:45:01 CST