The adodbapi documentation and code implies that with autocommit = False I
should only have to call commit (and possibly rollback) and if using the
connection as a context manager not even those are required.
If autocommit = False is passed on the initial connect the __init__ of the
connector handles BeginTrans and subsequent commit and rollbacks also leave
me with an open trans.
But if I do this:
conn = adodbapi.connect(conn_args, autocommit=True)
conn.autocommit = False
with conn:
cur = conn.cursor()
cur.execute("insert into table1 (col1) values (?)", ('row5', ))
print 'inserted a row'
I get an exception that there is not an existing transaction to commit.
I created a quick subclass of the Connect class that handles the
__setattr__ for 'autocommit' by calling self.BeginTrans() if autocommit =
False
class MyConnection(adodbapi.Connection):
""""""
def __setattr__(self, name, value):
super(self.__class__, self).__setattr__(name, value)
if name == 'autocommit':
if (not self._autocommit
and self.supportsTransactions
and self.transaction_level == 0):
self.transaction_level = self.connector.BeginTrans()
But of course I also had to re-implement the adodbapi.connect to use my
Connection class (is there a better way?).
I think what I'm getting at is that allowing the caller to change the
autocommit attribute to False on the instance but not beginning a trans (as
would happen if the autocommit = False was passed in connect()) seems
inconsistent.
On Mon, Oct 24, 2016 at 9:00 AM, <[email protected]> wrote:
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> 1. Re: adodbapi changing autocommit (Tim Roberts)
>
>
> ---------- Forwarded message ----------
> From: Tim Roberts <[email protected]>
> To: "[email protected]" <[email protected]>
> Cc:
> Date: Sun, 23 Oct 2016 14:59:27 -0700
> Subject: Re: [python-win32] adodbapi changing autocommit
> On Oct 22, 2016, at 9:42 PM, Max Slimmer III <[email protected]> wrote:
> >
> > Setting connection.autocommit = False does not cause a
> > connection.connector.BeginTrans() and so any subsequent
> > connection.commit() raises an exception that there is no open
> > transaction. Is this by design and I'm supposed to explicitly call
> > BeginTrans() when switching autocommit off?
>
> Yes, that's exactly the tradeoff. If you have auto commit on, ADO will
> wrap each operation in a transaction. If you have auto commit off, then
> you have to insert the transaction markers yourself.
> —
> Tim Roberts, [email protected]
> Providenza & Boekelheide, Inc.
>
>
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--
--Max III
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