Message-ID: <417FA067.5030506@inpris.ru>
Date: Wed, 27 Oct 2004 17:19:35 +0400
From: "Dmitry P. Ovechkin" <odp@inpris.ru>
User-Agent: Mozilla Thunderbird 0.7.1 (X11/20040626)
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To: pgsql-sql@postgresql.org
Subject: RULE and default nextval() column
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Hello.
I'mtrying to implement history tables using rules.
I have
test_table
----------
create sequence history_seq start 1;
create sequence test_sequence;
# source table
drop table test_table;
create table test_table (
i integer default nextval('test_sequence'),
c character(10)
);
# history table
create table test_table_history (
hist integer default nextval('history_seq'),
i integer,
c character(10)
);
# rule to save history
create rule test_table_history_insert as on insert to test_table do
insert into test_table_history values ( nextval('history_seq'),
         new.i,
         new.c
         );
#
Then I try to insert into test_table;
test=> insert into test_table values( nextval('test_sequence'), 'a');
INSERT 3299176 1
test=> insert into test_table (c) values('a');
INSERT 3299178 1
drweb=> select * from test_table;
  i |     c
---+------------
  1 | a
  3 | a
(2 rows)

test=> select * from test_table_history;
  hist | i |     c
------+---+------------
     1 | 2 | a
     2 | 4 | a
(2 rows)

==========
Problem is : value of "i" field increments during insertion into both 
test_table and test_table history.
This also happens if I omit "i" in insert statement and let it be filled 
by default.
Can something be done to avoid it?

Sincerely, Dmitry Ovechkin.