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Groups > comp.lang.python > #50260
On 07/09/2013 01:38 AM, Frank Millman wrote:
>
> "Ian Kelly" <ian.g.kelly@gmail.com> wrote in message
> news:CALwzid=FzgjPebifx1stDBkh8iwLtWggwwPTPhZ1ykYg+05wEg@mail.gmail.com...
>> On Tue, Jul 9, 2013 at 1:35 AM, Frank Millman <frank@chagford.com> wrote:
>>> When any of them need any database access, whether for reading or for
>>> updating, they execute the following -
>>>
>>> with db_session as conn:
>>> conn.transaction_active = True # this line must be added if
>>> updating
>>> conn.cur.execute(__whatever__)
>>
>> I'd probably factor out the transaction_active line into a separate
>> DbSession method.
>>
>> @contextmanager
>> def updating(self):
>> with self as conn:
>> conn.transaction_active = True
>> yield conn
>>
>> Then you can do "with db_session" if you're merely reading, or "with
>> db_session.updating()" if you're writing, and you don't need to repeat
>> the transaction_active line all over the place.
>>
>
> I'll bear it in mind, but I will have to expend some mental energy to
> understand it first <g>, so it will have to wait until I can find some time.
You could also do it like this:
def updating(self):
self.transaction_active = True
return self
and a sample object:
class Tester(object):
def __init__(self):
self.transaction_active = False
print 'initializied'
def __enter__(self, *args):
print '__enter__: transaction_active =', self.transaction_active
return self
def __exit__(self, *args):
self.transaction_active = False
print '__exit__: transaction_active =', self.transaction_active
return
def updating(self):
self.transaction_active = True
print 'updating: self.transaction_active =', self.transaction_active
return self
with Tester() as conn:
print 'in first with block'
print '-' * 50
with Tester().updating() as conn:
print 'in second with block'
with it's test run:
ethan@hydra:~$ python test_cm.py
initialized
__enter__: transaction_active = False
in first with block
__exit__: transaction_active = False
--------------------------------------------------
initialized
updating: self.transaction_active = True
__enter__: transaction_active = True
in second with block
__exit__: transaction_active = False
--
~Ethan~
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Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-04 03:27 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-04 14:07 +1000
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-04 05:32 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-04 15:47 +1000
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-04 16:38 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-05 02:58 +1000
Re: Default scope of variables Wayne Werner <wayne@waynewerner.com> - 2013-07-07 08:13 -0500
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-07 23:43 +1000
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-07 16:03 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-08 10:46 +1000
Re: Default scope of variables alex23 <wuwei23@gmail.com> - 2013-07-09 14:52 +1000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-09 15:07 +1000
Re: Default scope of variables alex23 <wuwei23@gmail.com> - 2013-07-09 16:08 +1000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-09 16:13 +1000
Re: Default scope of variables "Frank Millman" <frank@chagford.com> - 2013-07-09 09:35 +0200
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-09 17:45 +1000
Re: Default scope of variables Ian Kelly <ian.g.kelly@gmail.com> - 2013-07-09 01:56 -0600
Re: Default scope of variables "Frank Millman" <frank@chagford.com> - 2013-07-09 10:22 +0200
Re: Default scope of variables "Frank Millman" <frank@chagford.com> - 2013-07-09 10:38 +0200
Re: Default scope of variables Ethan Furman <ethan@stoneleaf.us> - 2013-07-09 09:07 -0700
Re: Default scope of variables Ian Kelly <ian.g.kelly@gmail.com> - 2013-07-09 10:44 -0600
Re: Default scope of variables Ethan Furman <ethan@stoneleaf.us> - 2013-07-09 10:23 -0700
Re: Default scope of variables Ian Kelly <ian.g.kelly@gmail.com> - 2013-07-09 12:41 -0600
Re: Default scope of variables Ethan Furman <ethan@stoneleaf.us> - 2013-07-09 12:19 -0700
Re: Default scope of variables "Frank Millman" <frank@chagford.com> - 2013-07-10 07:54 +0200
Re: Default scope of variables Ian Kelly <ian.g.kelly@gmail.com> - 2013-07-10 09:42 -0600
Re: Default scope of variables Ethan Furman <ethan@stoneleaf.us> - 2013-07-10 08:29 -0700
Re: Default scope of variables "Frank Millman" <frank@chagford.com> - 2013-07-11 07:52 +0200
Re: Default scope of variables Ethan Furman <ethan@stoneleaf.us> - 2013-07-07 09:52 -0700
Re: Default scope of variables Ethan Furman <ethan@stoneleaf.us> - 2013-07-07 11:59 -0700
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-08 10:48 +1000
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-08 02:23 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-08 13:11 +1000
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-08 05:00 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-08 15:14 +1000
Re: Default scope of variables Peter Otten <__peter__@web.de> - 2013-07-04 08:48 +0200
Re: Default scope of variables Ian Kelly <ian.g.kelly@gmail.com> - 2013-07-04 01:12 -0600
Re: Default scope of variables Dave Angel <davea@davea.name> - 2013-07-04 03:06 -0400
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-04 15:52 +0000
Re: Default scope of variables Rotwang <sg552@hotmail.co.uk> - 2013-07-04 17:54 +0100
Re: Default scope of variables Peter Otten <__peter__@web.de> - 2013-07-04 20:36 +0200
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-05 01:04 +0100
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-05 01:24 +0000
Re: Default scope of variables Dave Angel <davea@davea.name> - 2013-07-04 22:03 -0400
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-05 03:29 +0100
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-05 03:27 +0100
Re: Default scope of variables Rotwang <sg552@hotmail.co.uk> - 2013-07-05 07:28 +0100
Re: Default scope of variables Neil Cerutti <neilc@norwich.edu> - 2013-07-05 13:24 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-05 23:43 +1000
Re: Default scope of variables Neil Cerutti <neilc@norwich.edu> - 2013-07-05 15:36 +0000
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-07 16:08 +0000
Re: Default scope of variables Neil Cerutti <neilc@norwich.edu> - 2013-07-08 11:54 +0000
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-08 14:14 +0100
Re: Default scope of variables Lele Gaifax <lele@metapensiero.it> - 2013-07-04 14:43 +0200
Re: Default scope of variables Wayne Werner <wayne@waynewerner.com> - 2013-07-04 10:45 -0500
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-04 05:30 +0100
Re: Default scope of variables Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-04 05:45 +0000
Re: Default scope of variables Chris Angelico <rosuav@gmail.com> - 2013-07-04 14:36 +1000
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-04 06:09 +0100
Re: Default scope of variables Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-08 17:58 +0100
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