To: David Wheeler <david@wheeler.net>
Cc: dbi-dev@perl.org, pgsql-interfaces@postgresql.org
Subject: Re: DBD::PostgreSQL 
In-reply-to: <0907BA9A-FB11-11D6-93B3-0003931A964A@wheeler.net> 
References: <0907BA9A-FB11-11D6-93B3-0003931A964A@wheeler.net>
Comments: In-reply-to David Wheeler <david@wheeler.net>
	message dated "Mon, 18 Nov 2002 08:16:03 -0800"
Date: Mon, 18 Nov 2002 11:19:25 -0500
Message-ID: <29660.1037636365@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

David Wheeler <david@wheeler.net> writes:
> On Sunday, November 17, 2002, at 10:15  PM, Tom Lane wrote:
>> Both of these seem pretty bogus to me.  Ideally the driver should not
>> issue a "begin" until the application issues the first command of the
>> new transaction.  Otherwise you get into scenarios where idle
>> connections are holding open transactions, and ain't nobody gonna be
>> happy with that.

> Okay. I think I'll use a flag in the driver to track when it's in a 
> transaction, and do the right thing in the begin and rollback functions.

I think someone else said that the DBD framework already includes such a
flag ("BegunWork"?) --- if so, you should surely use that one.

> So, if I understand you correctly, PostgreSQL's PREPARE statement 
> *requires* data typing in its syntax?

Yup.

> If so, is there an 
> easy/straight-forward way to ask the server what the data types for 
> each column are before executing the PREPARE?

There are various ways to retrieve the datatypes of the columns of a
table, but I'm not sure how that helps you to determine the parameter
types for an arbitrary SQL command to be prepared.  Are you assuming
a specific structure of the command you want to prepare?

			regards, tom lane