On 4/19/06, Michael Van Canneyt <[EMAIL PROTECTED]> wrote:
> On Wed, 19 Apr 2006, Adrian Maier wrote:
>
> > On 4/19/06, Joost van der Sluis <[EMAIL PROTECTED]> wrote:
> >>> Is this a problem with PostrgreSQL itself or the component in lazarus
> >>> wrapping it?
> >>
> >> It's a problem of postgres. A transaction 'block' is started with the
> >> sql-command 'begin', from that comand on, all queries are executed
> >> within that transaction. Using another connection is not possible.
> >> Unless, offcourse, you start a new connection. Or closes the transaction
> >> (commit, rollback etc)
> >
> > Please pardon me for jumping in the middle of the thread, but your
> > phrase made me really curious. The behaviour you described seems
> > to be the normal one, once you execute "begin" (transaction) . What
> > other behaviour would someone expect postgres to have ?
>
> To allow several concurrent transactions.
Is this implemented inside the database engine, as some special SQL
commands ? Is it possible to start more transactions simultaneously
from firebird's interactive utility? how does one specify that a certain
SQL command has to be executed inside one transaction or another ?
> Interbase/Firebird allows to start several concurrent transactions in
> 1 connection. AFAIK Oracle and MS-SQL too (named transactions).
I'm not sure about this.
Oracle has named transactions, but those are just labels that are given
to long-running transaction - so that they can be easier identified. Also,
in Oracle it is possible that a stored procedure be executed in an
'autonomous' transaction ( i've used this once for writing a procedure
that wrote debugging information to a table ; in case of error the messages
would have been rolled back unless they were inserted by an autonomous
transaction). But i believe that these autonomous transactions are a different
beast from the feature we are talking about.
> This is extremely handy.
I understand this.
Yet, my feeling is that this feature is an interbase/firebird
extension , and that
it would be possible to achieve the same by using more standard features like
cursors and savepoints.
Adrian Maier
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