Am Sun, Sep 08, 2024 at 12:48:50PM +1200 schrieb Greg Ewing via Python-list:
> On 8/09/24 9:20 am, Karsten Hilbert wrote:
> > try:
> > do something
> > except:
> > log something
> > finally:
> > .commit()
> >
> >cadence is fairly Pythonic and elegant in that it ensures the
> >the .commit() will always be reached regardless of exceptions
> >being thrown or not and them being handled or not.
>
> That seems wrong to me. I would have thought the commit should only
> be attempted if everything went right.
>
> What if there's a problem in your code that causes a non-SQL-related
> exception when some but not all of the SQL statements in the
> transaction bave been issued? The database doesn't know something
> has gone wrong, so it will happily commit a partially-completed
> transaction and possibly corrupt your data.
A-ha !
try:
run_some_SQL_that_succeeds()
print(no_such_name) #
tongue-in-cheek
1 / 0 # for
good measure
except SOME_DB_ERROR:
print('some DB error, can be ignored for now')
finally:
commit()
which is wrong, given that the failing *Python* statements
may very well belong into the *business level* "transaction"
which a/the database transaction is part of.
See, that's why I was asking in the first place :-)
I was overlooking implications.
Karsten
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