Re: [SQLObject] Join tables

[John B. <jb...@te...>]

On Tuesday 11 November 2003 17:41, Ian Bicking wrote:
> On Nov 11, 2003, at 11:20 AM, John Baker wrote:
> > Ok :-)
> >
> > So please provide me with some code that will do my
> > Ward/Constituency/Area
> > and 'something has many Areas' example... :)
>
> def oneOrNone(val):
>      try:
>          return val[0]
>      except IndexError:
>          return None
>
> class Area(SQLObject):
>      # Really should be a one-to-one join for these...
>      def _get_ward(self):
>          return oneOrNone(Ward.selectBy(area=self))
>      def _get_consituency(self):
>          return oneOrNone(Constiuency.selectBy(area=self))
>      ...
>
> class Ward(SQLObject):
>      area = ForeignKey('Area')
>
> ...
>
>
> Ta-da!  More work if you want to fold the attributes of the connected
> tables into the original Area object.  I'm sure you won't be satisfied
> by this, but it's only bad if you come into the problem with
> inheritance fixed in your mind.  I tend to come at the problem thinking
> in terms of related objects, which works fine right now, and with which
> you can handle the same problems, even if in a different way.

Well attributes in area would be nice, but it'll do for now :)


-- 
John Baker, Senior Developer, TEAM.
http://www.teamenergy.com
Views expressed in this mail are my own.