On Monday 09 June 2008 03:56:20 Michael Bayer wrote:
> On Jun 8, 2008, at 5:02 AM, [EMAIL PROTECTED] wrote:
> > hi
> > i'm trying to make a metainfo extractor off some relation
> > attribute. by metainfo i mean the klas and attr-name of this and
> > of the other side of the relation-attribute, or of the parent or
> > child of the relation regardless the start point.
> >
> > e.g. possible usage and testing invariants is like:
> > a = about_relation( someklas.someproperty)
> > print a.name, a.klas, 'is_parent:', a.is_parent
> > assert a.thisside == a
> > b = a.otherside
> > print b.name, b.klas, 'is_parent:', b.is_parent
> > assert a.otherside.otherside == a
> > if a.is_parent:
> > assert a.child is a.otherside
> > assert a.parent is a.thisside
> > else:
> > assert a.parent is a.otherside
> > assert a.child is a.thisside
> > e.g. if Parent.kids / Kid.parent are 1:many:
> > print about_relation( Parent.kids).otherside.name -> 'mama'
> > print about_relation( Parent.kids).otherside.klas -> 'Kid'
> > print about_relation( Parent.kids).child.klas -> 'Kid'
> > print about_relation( Kid.parent).child.klas -> 'Kid'
> > print about_relation( Kid.parent).parent.klas -> 'Parent'
> > print about_relation( Kid.parent).otherside.name -> 'kids'
>
> def about_relation(descriptor):
> prop = descriptor.property
> return {
> 'child':{'name': prop.key, 'klas': prop.mapper.class_}
> 'parent':{'klas':prop.parent.class_}
> }
>
> I don't understand what "is_parent" means (nor 'thissside' and
> 'otherside'). every relation has a "parent" and "child".
given the descriptor Kid.parent, it is considered "thisside", and the
other end descriptor (Parent.kids) is "otherside"; is_parent is which
role the particular descriptor is, from a 1-to-many terminology.
maybe i use wrong naming ...
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