Re: on error resume next

[Andreas Wenk <a(dot)wenk(at)netzmeister-st-pauli(dot)de>]

Jasmin Dizdarevic wrote:
> hi,
>  
> can i use savepoints to realize something like "on error resume next"?
>  
> i've got the following situation:
>  
> begin;
> 1. create view user001.accounts as select * from base.accounts;
> 2. grant select on user001.accounts to loginuser001;
> commit;
>  
> begin;
> 3. create view user002.accounts as select * from base.accounts;
> 4. grant select on user002.accounts to loginuser002;
> commit;
>  
>  
> my goal is to avoid execution stop, if one of the transactions fail.
> let's say line 1 throws an error it should go further to line 3.
>  
> any ideas?
>  
> thank you.
>  
> jasmin

AFAIK it's not possible. A transaction is kind of a container with a 
positive or negative result. If one of the queries fails in between a 
transaction, it will be rolled back after a commit. What you can do with 
savepoints is the following:

usage=# CREATE TABLE test (id serial, content text);
usage=# BEGIN;
usage=# INSERT INTO test (content) VALUES ('first stuff');
usage=# SAVEPOINT s1;
usage=# INSERT INTO test (content) VALUES ();
ERROR:  syntax error at or near ")"
usage=# ROLLBACK TO SAVEPOINT s1;
ROLLBACK
usage=# SELECT * FROM test;
 id |   content
----+--------------
  1 | first stuff
(1 row)

usage=# COMMIT;
COMMIT
usage=# SELECT * FROM test;
 id |   content
----+--------------
  1 | first stuff
(1 row)

The second INSERT statement fails. If you would go further with insert 
statements and then fire a COMMIT at the end, nothing would be inserted 
into the table. But if you fire a ROLLBACK TO SAVEPOINT s1, at least the 
data of the first INSERT statement are written.

So maybe this is a start help for creating some logic to get something 
like 'on error resume next'.

Cheers

Andy