Default scope of variables

[Frank Millman]

"Ian Kelly" <ian.g.kelly at gmail.com> wrote in message 
news:CALwzid=FzgjPebifx1stDBkh8iwLtWggwwPTPhZ1ykYg+05wEg at mail.gmail.com...
> On Tue, Jul 9, 2013 at 1:35 AM, Frank Millman <frank at 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.

> I would also probably make db_session a factory function instead of a 
> global.

It is not actually a global. When I create a new session, I create a 
db_session instance and store it as a session attribute. Whenever I create a 
database object during the session, I pass in the instance as an argument, 
so they all share the same one.

Frank