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Currval and transactions.

From: "Adam Gentz" <adamg(at)bizx(dot)com>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: Currval and transactions.
Date: 2009-12-02 21:07:46
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-novice

Ok, so i'm trying to insert a row and return the id of that row as supplied by the DEFAULT directive.

And i'm stuck on v8.1.x or i'd use the "RETURNING" construct.

And i've already found a message on this list that suggests a structure such as:

INSERT INTO $tableName 
( instance_name, instance_id )
( '$instanceName', DEFAULT );
SELECT CURRVAL('".$tableName."_instance_id_seq');

however i've found that this structure doesnt return anything, it completes successfully but i get no results, when i run it through pgadmin i get the message: 
Query result with 1 rows discarded.

Query returned successfully with no result in 2 ms.

if i drop the transaction declarations at the top and bottom i get the desired result, the id of the most recently created row, but i want to make sure that by dropping those declarations, i'm not going to be subject to a race condition.  Basically i'm asking if the two queries, when sent together, will be executed in a single transaction, or in two separate transactions which could be subject to said race condition.

Thanks in advance for your help.

Adam Gentz
Web Developer
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Subject: Re: initdb fails in win xp
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