Re: Re: psycopg3 transactions

On Thu, 14 Oct 2021, 11:05 Karsten Hilbert, <Karsten(dot)Hilbert(at)gmx(dot)net> wrote:

> >My conclusion is that the only sane thing to do is:
> >1. Only ever create connections in autocommit mode.
> >2. Only ever use `with connection.transaction()` to control transactions.
> >3. Forget that `connection.commit()` and `connection.rollback()` exist,
> and never use them.
>
> What if you need to rollback a hitherto valid transaction ?
>
> Transactions are there for a reason. It seems best to explicitely use them
> ?
>

I'm not sure I fully understand your question/statement but let me try to
respond.

We are still "using transactions", just with more precise, more explicit*,
and more flexible* semantics, represented by a context manager.

Rolling back a transaction is possible by raising a Rollback exception
within a block.

I hope this answers your question but if not please describe the scenario
you are thinking about.

Dani

(*More explicit because in the conventional autocommit=false approach, the
beginning of the transaction is an implicit side-effect of executing
another statement, which may or may not actually begin a transaction
depending on whether one is in progress. More flexible because you can have
nested transaction blocks which operate in an independent and composable
way.)