Can deferrable etc be used when deleting primary key records (master
table), then reinserting them without losing foreign key records
(slave table)? I ask because in our testing we can't; we lose the
foreign key records in the slave table. I'm guessing we are trying to
abuse the feature.
here's a test script we tried:
drop table master;
CREATE TABLE master ( id integer NOT NULL, Primary Key (id)
);
insert into master values (1);
insert into master values (2);
drop table slave;
create table slave ( id int, foreign key (id)references master (id) on update restrict on
delete cascade INITIALLY DEFERRED)
;
insert into slave values (1);
insert into slave values (1);
Then:
test=# BEGIN;
BEGIN
test=# SET CONSTRAINTS ALL DEFERRED;
SET CONSTRAINTS
test=# delete from master;
DELETE 2
test=# insert into master values (1);
INSERT 20959595 1
test=# insert into master values (2);
INSERT 20959596 1
test=# select * from slave;id
---- 1 1
(2 rows)
test=# commit;
COMMIT
test=# select * from slave;id
----
(0 rows)
test=#
Our hope was that after the commit, slave would retain the original
rows.
cheers
--
Dan Langille
