Re: Double sequence increase on single insert with RULE on

Ok :) Then I found the solution in this partical case:
CREATE RULE test1_on_insert AS ON INSERT TO test1 DO INSERT INTO
test_log1 (qid) VALUES ( (SELECT lastval()) );
With this rule all inserts are working as expected :)

Thank you for you advise :)

Sarunas

Michael Fuhr wrote:

>On Wed, Nov 16, 2005 at 10:31:10AM +0200, Sarunas Krisciukaitis wrote:
>
>
>>I understand that RULES are like macros.
>>Strangest thing here is that INSERT to test1 will touch only one
>>sequence: test1_id_seq.
>>And it increments test1_id_seq twice during insert with RULE.
>>
>>
>
>Yes, that's a well-known effect of rewriting a query that includes
>a call to nextval().  NEW.id in the rule doesn't refer to the value
>that's inserted, but rather to the expression that's evaluated to
>get that value.  Since you didn't provide a value for id it gets
>the default: nextval('test1_id_seq').  That expression is used in
>both inserts, so the sequence gets incremented twice.  See the
>archives for numerous past discussions of this behavior.
>
>
>