Re: On duplicate ignore

Just create a unique index on EMAIL column and handle error if it comes

Thanks,
Atul Goel

-----Original Message-----
From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-owner(at)postgresql(dot)org] On Behalf Of Gnanakumar
Sent: 18 January 2012 11:04
To: pgsql-general(at)postgresql(dot)org
Subject: [GENERAL] On duplicate ignore

Hi,

Ours is a web-based application. We're trying to implement ON DUPLICATE IGNORE for one of our application table, named EMAILLIST. After a quick Google search, I'm finding the following "easy & convenient" single SQL statement syntax to follow with:

INSERT INTO EMAILLIST (EMAIL)
SELECT 'john(at)example(dot)net'
WHERE NOT EXISTS (SELECT 1 FROM EMAILLIST WHERE EMAIL = 'john(at)example(dot)net');

My question is, in a single threaded INSERT, this will *definitely* work.
Since ours is a web-based application, will this work out in a concurrent multi-threaded environment too? In other words, will it be truly unique when INSERT calls are concurrent?

Regards,
Gnanam

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