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Re: [Gnumed-devel] what about commit?


From: Karsten Hilbert
Subject: Re: [Gnumed-devel] what about commit?
Date: Mon, 22 Sep 2003 19:37:22 +0200
User-agent: Mutt/1.3.22.1i

> What does that mean " real concurrent atomic transactions inside of the 
> scope of a single client connection" ?
> With one connection, I didn't think you could have more than one 
> transaction
What makes you think that ? You can just fine BEGIN COMMIT
BEGIN COMMIT. Just not concurrently.

> ( that's why the commit() operation is
> on the connection object).
This seems odd at first sight but makes sense when you
consider that you can (should be able to ?) open and
close several cursors in one connection. The commit then
simply commits all outstanding data changes.

> The semantics is that one connection object per transaction : otherwise 
> you have to start labelling the transactions per connection ;
Why would that be ? A connection is a channel through which
commands and data are sent to the database. An SQL string is a
meaningful parcel. A transaction is like a UPS truck. Either
all the parcels get there or the UPS truck crashes and no
parcels get there at all. Several UPS trucks can drive along
the channel. But not in the same spot. So, yes, you want to
get your own road. But you don't need to build a new road
every time you need it. Just send off the trucks one after the
other.

Karsten
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