From: Jonathan Gardner <jgardner@jonathangardner.net>
To: Anagha Joshi <ajoshi@nulinkinc.com>
Cc: pgsql-admin@postgresql.org
Cc: pgsql-sql@postgresql.org
Subject: Re: Latest transcation
Date: Fri, 20 Jun 2003 06:43:18 -0700
Message-ID: <200306200643.37298.jgardner@jonathangardner.net> (raw)
In-Reply-To: <FF851C7EEB75954F9BCFB5CA117AB1EC092832@delta.nulinkinc.com>
References: <FF851C7EEB75954F9BCFB5CA117AB1EC092832@delta.nulinkinc.com>
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On Friday 20 June 2003 01:27, Anagha Joshi wrote:
> Yes...I'm aware of that and have tried also by maintaining extra table.
> But how to to the following:
> 1. If insertion takes place, I want to return to the client the
> values (with field names of course) which are inserted into the
> tables. In each case table might be different.
>
When you insert a single row, PostgreSQL returns the OID of that row. Just
follow up with a select (SELECT * FROM <your table> WHERE OID=<the oid>) and
you'll get all the info you need.
> 2. If modification takes places, I want to know the values which
> are modified with field names and return them to the client.
>
You can do that by checking what is different between the data you inserted
and the data you get from the select statement.
> More precisely,
> My C++ client --
> '
> '
> "
> Transcation begin
> insert/update query to the backend is fired.
> //control is tranferred to the trigger
> //After trigger procedure is executed, I want at this
> point the values inserted/modified so //as to pass them back
> Transcation end
> '
> '
>
I don't think it can work the way you would like it. Try this algorithm.
For insert:
1. Insert query is run. (Trigger, other table inserts/updates performed)
2. With the OID from the insert, select the data.
For Update:
1. Update query is run. (Triggers, etc, are run as well).
2. With the OID (or Primary Key), select the data you just updated.
You can turn these two procedures into a stored procedure pretty easily. This
way, all you do is call a stored procedure, and it will pass back all the
data you need. You get a free transaction block inside the stored procedure
as well.
- --
Jonathan Gardner <jgardner@jonathangardner.net>
(was jgardn@alumni.washington.edu)
Live Free, Use Linux!
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To: pgsql-sql@postgresql.org
Cc: jgardner@jonathangardner.net, ajoshi@nulinkinc.com, pgsql-admin@postgresql.org
Subject: Re: Latest transcation
In-Reply-To: <200306200643.37298.jgardner@jonathangardner.net>
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