From: Jonathan Gardner <jgardner@jonathangardner.net>
To: "Anagha Joshi" <ajoshi@nulinkinc.com>
Subject: Re: Latest transcation
Date: Fri, 20 Jun 2003 06:43:18 -0700
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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=
=20
follow up with a select (SELECT * FROM <your table> WHERE OID=3D<the oid>) =
and=20
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=
=20
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. Th=
is=20
way, all you do is call a stored procedure, and it will pass back all the=
=20
data you need. You get a free transaction block inside the stored procedure=
=20
as well.

- --=20
Jonathan Gardner <jgardner@jonathangardner.net>
(was jgardn@alumni.washington.edu)
Live Free, Use Linux!
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