Re: Is it possible to redirect an update/insert/delete to a different table?

Andy Ballingall <andy(at)areyoulocal(dot)co(dot)uk> schrieb:

> Hello Jaime,
>
> I'm still not quite clear.
>
> Say I have a number of different updates on a table 'apples' in my code,
> including:
>
> UPDATE apples set pips=6 and color='yellow' where id=3;
> UPDATE apples set size=10 where id=6;
>
> What would a rule look like which, when *any* update is attempted on the
> apples table, will instead apply the update to a different table - 'pears'.

Try it.

test=# create table apples (id int, name1 text, name2 text);
CREATE TABLE
test=# create table pears (id int, name1 text, name2 text);
CREATE TABLE
test=# create rule apples_pears_update as on update to apples do instead
update pears set name1= NEW.name1, name2=NEW.name2 where id=NEW.id ;
CREATE RULE
test=# insert into apples values (1, 'a', 'a');
INSERT 0 1
test=# insert into pears values (1, 'a', 'a');
INSERT 0 1
test=#
test=# update apples set name1='b' where id = 1;
UPDATE 1
test=# select * from pears ;
id | name1 | name2
----+-------+-------
1 | b | a
(1 row)

test=# update apples set name2='c' where id = 1;
UPDATE 1
test=# select * from pears ;
id | name1 | name2
----+-------+-------
1 | a | c
(1 row)

test=# update apples set name1='e', name2='e' where id = 1;
UPDATE 1
test=# select * from pears ;
id | name1 | name2
----+-------+-------
1 | e | e
(1 row)

>
> -----Original Message-----

Please, no top-posting.

HTH, Andreas
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