Sanjay wrote:
>>Can you flesh out your use case a little bit and tell why you can't solve
>>the problem with inheritance or a meta class?
>
>
> I have to study about metaclass and see whether this can be handled. It
> seemed inheritence is not working.
>
> PROBLEM: Separating plumbing code and business logic while using
> SQLAlchemy ORM.
>
(snip)
> DB definitions and plumbing code goes into one module, say db.py:
>
> import sqlalchemy.mods.threadlocal
> from sqlalchemy import *
>
> global_connect('postgres://userid:[EMAIL PROTECTED]:5432/tm')
> person_tbl = Table('person', default_metadata, autoload = True)
> class Person(object):
> pass
(snip)
> Business logic in another module, say bo.py
>
> Class PersonBO(Person):
> def Block():
> blocked = True
<OT>
shouldn't it be:
class PersonBO(Person):
def block(self):
self.blocked = True
</OT>
> While using PersonBO in another module, like this:
>
> p1 = PersonBO(passport = "[EMAIL PROTECTED]", first_name='john',
> last_name='smith', email = "[EMAIL PROTECTED]")
> p2 = PersonBO(passport = "[EMAIL PROTECTED]", first_name='ed',
> last_name='helms', email = "[EMAIL PROTECTED]")
> p3 = PersonBO(passport = "[EMAIL PROTECTED]", first_name='jonathan',
> last_name='lacour', email = "[EMAIL PROTECTED]")
>
> # add a contact
> p1.contacts.append(Contact(person=p2))
>
> the following error message occurs:
>
> AttributeError: 'PersonBO' object has no attribute 'contacts'
Strange.
> What I guess, from my limited knowledge of the technologies involved,
> is that assign_mapper does some magic only on Person class, and things
> work. But after inheritence, it is not working.
Anyway, there are other ways to reuse implementation, like
composition/delegation. You may want to have a look at
__getattr__/__setattr__ magic methods.
> As far as my project is concerned, I have found out some other way of
> doing the things,
Care to explain your solution ?
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])"
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