Thanks a lot!
I think your suggestion will be ok for me for now.
Have a good day,
tamas
On Thu, Jul 17, 2008 at 9:55 AM, Michael Bayer <[EMAIL PROTECTED]>
wrote:
>
>
> On Jul 16, 2008, at 4:43 PM, Tamas wrote:
>
> >
> > Hi,
> >
> > I am not a professional coder; hobby-like thing.
> > I would like to encapsulate my table definitions in a new class:
> >
> > class MyTable( Table):
> > def __init__( self, metadata):
> > Table.__init__( self, my_table_name, metadata, col1, col2...)
> >
> > metadata = MetaData()
> > table = MyTable( metadata)
> >
> > Traceback (most recent call last):
> > File "create_tables.py", line 11, in <module>
> > table = MyTable( metadata)
> > TypeError: __call__() takes at least 3 arguments (2 given)
> >
> > *******
> > I tested different things and I have the feeling that it is not
> > possible to subclass the Table class.
> > Is this true?
> >
> > If no: what is the mistake I make?
> >
> > If yes: why? does Table class have some special decoration or
> > something like that?
> > How do you avoid to define your table in every script you write to
> > use that table with its corresponding class?
>
>
> its possible, but tricky since the creation of a Table is routed
> through a metaclass which ensures that only one instance of Table for
> a particular name within the MetaData exists, i.e.:
>
>
> -> t1 = Table('t1', metadata, ...)
> -> t2 = Table('t1', metadata, ...)
> -> t1 is t2
> True
>
> So true subclassing here would require that you also subclass the
> metaclass to do what you want here, which is probably not a good idea
> since thats not public API stuff.
>
> If its just a creational pattern you're looking for, I'd suggest using
> a def instead of a class:
>
> def MyTable(metadata):
> return Table('myname', metadata, ...)
>
> If there's other behavior you're looking for, let us know what it is
> and we'll see if we can accomodate you.
>
>
>
> >
>
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