A question on decorators

[Gabriel Genellina]

En Wed, 26 Mar 2008 18:01:31 -0300, George Sakkis  
<george.sakkis at gmail.com> escribió:

> On Mar 26, 3:41 pm, Tim Henderson <tim.t... at gmail.com> wrote:
>
>> I am using mysql, and sqlite is not appropriate for my situation since
>> some of the databases and tables I access are being accessed by other
>> applications which are already written and live. I am not using the
>> SQLAlchemy or SQLObject, because I didn't want too (although in the
>> future I may consider using them).
>
> I'd strongly second looking into SQLAlchemy; from what you wrote, I
> suspect sooner or later you'll end up creating (to paraphrase
> Greenspun) an ad hoc, informally-specified, bug-ridden, slow
> implementation of half of SQLAlchemy.

You beat me to say that, but using SQLObject instead.
Moreover, the OP is looking for the PersistentDict and PersistentList  
classes that ZODB uses.
I'm not sure that triggering a database write for each and every modified  
attribute is a good thing; I'd use a "dirty" flag instead (ZODB uses  
_p_changed) and write all modifications at the end.
Since not all methods modify the object contents, using a metaclass to  
flag all of them isn't a good idea either. I'd use a decorator; after all,  
they're not so many methods; if you inherit from DictMixin you only have  
to write __getitem__, __setitem__, __delitem__ and keys(), and of those,  
only __setitem__ and __delitem__ modify the object.

-- 
Gabriel Genellina