On 07/09/2013 10:54 PM, Frank Millman wrote:
"Ian Kelly" <ian.g.ke...@gmail.com> wrote in message
news:calwzidnf3obe0enf3xthlj5a40k8hxvthveipecq8+34zxy...@mail.gmail.com...
On Tue, Jul 9, 2013 at 10:07 AM, Ethan Furman <et...@stoneleaf.us> wrote:
You could also do it like this:
def updating(self):
self.transaction_active = True
return self
Yes, that would be simpler. I was all set to point out why this
doesn't work, and then I noticed that the location of the
"transaction_active" attribute is not consistent in the original code.
The DbSession class places it on self, and then the example usage
places it on the connection object (which I had based my version on).
Since that seems to be a source of confusion, it demonstrates another
reason why factoring this out is a good thing.
You had me worried there for a moment, as that is obviously an error.
Then I checked my actual code, and I find that I mis-transcribed it. It
actually looks like this -
with db_session as conn:
db_session.transaction_active = True
conn.cur.execute(...)
I am still not quite sure what your objection is to this. It feels
straightforward to me.
Here is one possible answer. Whenever I want to commit a transaction I have
to add the extra line. There is a danger that I could mis-spell
'transaction_active', in which case it would not raise an error, but would
not commit the transaction, which could be a hard-to-trace bug. Using your
approach, if I mis-spelled 'db_session.connect()', it would immediately
raise an error.
Is that your concern, or are there other issues?
That concern is big enough. I've been bitten by that type of thing enough in my own code to want to avoid it where
possible. Plus the `with db_session.updating() as conn:` saves keystrokes. ;)
--
~Ethan~
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