On May 30, 2007, at 7:27 AM, Lachlan Deck wrote:
* Changes to the validation rules to allow ObjEntity with no db
entity for abstract entities
The question of 'isAbstract' is merely a question of 'can instances
of this entity be instantiated'?
Certainly changes to validation rules are necessary. But it is
possible for an entity to be both abstract whilst having an
associated db entity (e.g., vertical inheritance where the
developer doesn't desire to instantiate instances of parent entity).
Right. I guess ObjEntity without a DbEntity feature can be tucked
onto one of the inheritance tasks.
* maybe also some runtime checks for abstract entity (???)
The only runtime checks I can foresee at the moment are:
- a CayenneRuntimeException for attempting to do a fetch on an
ObjEntity that has no associated db entity.
Other logic will need to be in place that determines how deep the
fetch is. e.g., if there's a SelectQuery on a parent entity that's
abstract then this would imply a deep fetch (i.e., of sub-entity
instances). If however the parent is not abstract then (even for
horizontal inheritance) instances of the parent are fetched
(resolving attributes appropriately from children for horizontal).
This may also be a part of the inheritance discussion, but here is a
one thing to note: SelectQuery (and other queries) supports
"setResolvingInherited", which is a deep-fetch vs. no-deep-fetch flag.
Andrus
