On 07/09/2013 01:38 AM, Frank Millman wrote:
"Ian Kelly" <ian.g.ke...@gmail.com> wrote in message
news:CALwzid=fzgjpebifx1stdbkh8iwltwggwwptphz1ykyg+05...@mail.gmail.com...
On Tue, Jul 9, 2013 at 1:35 AM, Frank Millman <fr...@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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