FreeTDS Development Group

[Michael Peppler <mpeppler AT peppler.org>]

On Wed, 2003-03-19 at 19:26, Chad Wagner wrote:
> --- ZIGLIO Frediano
> <Frediano.Ziglio AT vodafoneomnitel.it> wrote:
> > Currently FreeTDS make a connection for every
> > connection. 
> > Connection pooler do not work very well...
> > So all depend on mssql2k.
> 
> 
> Since this topic has come up, it doesn't appear that
> FreeTDS supports nested statement handles.  Anyone
> know if that is in the roadmap, or am I just doing
> something wrong?
> 
> I know this can be done with DBD::Oracle, and in
> general with PL/SQL in Oracle (nested cursors).
> 
> (DBD::Sybase -- When autocommit is off)
> 1. Panic: Can't have multiple statement handles on a
> single database handle when AutoCommit is OFF
> 
> 
> (DBD::Sybase -- When autocommit is on)
> 2. DBI::db=HASH(0x81b5d44)->disconnect invalidates 1
> active statement handle (either destroy statement
> handles or call finish on them before disconnecting)

The TDS protocol doesn't support multiple requests over the same
connection concurrently (unless one uses client side cursors).

Hence, DBD::Sybase *emulates* the ability to run multiple commands
(prepares()) over the same database connection by opening additional
database connections as needed. This feature is disabled when AutoCommit
is OFF because it would be too difficult for DBD::Sybase to make sure
that all the operations are properly committed or rolled back as
necessary.

I'm pretty sure that this BTW is documented in the DBD::Sybase man
page...

Michael
-- 
Michael Peppler                              Data Migrations, Inc.
mpeppler AT peppler.org                 http://www.mbay.net/~mpeppler
Sybase T-SQL/OpenClient/OpenServer/C/Perl developer available for short or 
long term contract positions - http://www.mbay.net/~mpeppler/resume.html