On Mar 29, 2008, at 3:16 PM, Kevin Menard wrote:
Essentially, what I'm seeing is that there is not a 1:1 correlation
between
relationships and their reverses.
True. A very good point. From what I can tell this may be another way
to tell what "redundant relationships" are.
In the case described both relationships are equally valid reverse
relationships. I wouldn't even call the situation ambiguous - it is
just two clearly defined relationships instead of one like we assumed
in the past.
So where do we go from here? There are two ways: we either change the
API to reflect 1:N natire of reverse relationship (and deal with it
everywhere throught the framework, e.g by setting multiple reverse
relationships inside CayenneDataObject, etc.) or disallow redundant
mapping explicitly. Either way it is a good idea to acknowledge this
scenario explicitly in some way, so that users know what they are
dealing with.
A lazy person in me votes for the later option. Or maybe not that
lazy? I always liked my object graph structure to avoid any
inconsistency (e.g. assume relationship cardinality that DB does not
enforce) and redundancy (e.g. RelatedEntity double relationships over
the same set of joins). So mentally I never allowed myself to map
anything like that, and never felt the need to do so. So maybe we
shouldn't enable this scenario, complicating the framework
significantly, just because we can?
Andrus
