Questions about rollback and commit

Fariba Noorbakhsh wrote:

Hello,

I tried Rollback after update or insert, but it doesn't work!
How can I rollback the update, insert or delete changes I have made in
pgsql?
Do I need to do commit after each update or insert?
Do update, insert or delete consider as transactions?

Every update and insert is wrapped in an implicit transaction. You can
however use transactions explicitly with 'begin;', you can then do
whatever sequence of updates and inserts until you give the 'commit;' or
'rollback;' command. When a SQL statement returns an error a rollback
will be issued by PostgreSQL and you would have to do the sequence
again. Next some examples from a psql session:

test=# insert into bar (foo) values ('foobar');
INSERT 15386527 1
test=# select * from bar;
foo
--------
foobar
(1 row)

test=# begin;
BEGIN
test=# insert into bar (foo) values ('barfoo');
INSERT 15386528 1
test=# select * from bar;
foo
--------
foobar
barfoo
(2 rows)

test=# rollback;
ROLLBACK
test=# select * from bar;
foo
--------
foobar
(1 row)

test=#

test=# begin;
BEGIN
test=# insert into bar (foo) values ('barfoo');
INSERT 15386529 1
test=# commit;
COMMIT
test=# select * from bar;
foo
--------
foobar
barfoo
(2 rows)

test=#

Regards,

Nils
--
Alles van waarde is weerloos
Lucebert

From: "Fariba Noorbakhsh" <fNoorbakhsh@tecways.com>

I tried Rollback after update or insert, but it doesn't work!
How can I rollback the update, insert or delete changes I have made in
pgsql?
Do I need to do commit after each update or insert?
Do update, insert or delete consider as transactions?

By default, every SQL statement is wrapped in its own transaction. You'll
need to issue a BEGIN if you want to be able to ROLLBACK.

HTH

- Richard Huxton