Tony Copping
2006-04-27 19:26:02 UTC
Maybe the whole concept of putting type information in the data is
the problem. I think the solution is either to have a separate
foreign key relationship to each entity. History for students would
have null school id, history for school would have null history Id.
If you want something more pure, try making the ChangeHistory a base
class and make subclasses for SchoolHistory and StudentHistory. Each
having the relationship to the entity for which history is to be
tracked.
This is similar to Nat's suggestion, only the subclassing is being
done on the history side - create a subclass of history for each
entity which needs history tracking.
T.
Suite L100, 239 - 10th Ave. SE
Calgary, AB T2G 0V9
the problem. I think the solution is either to have a separate
foreign key relationship to each entity. History for students would
have null school id, history for school would have null history Id.
If you want something more pure, try making the ChangeHistory a base
class and make subclasses for SchoolHistory and StudentHistory. Each
having the relationship to the entity for which history is to be
tracked.
This is similar to Nat's suggestion, only the subclassing is being
done on the history side - create a subclass of history for each
entity which needs history tracking.
T.
I can not figure out how to specify the changeHistoryType part of the
join in the EOModeler.
Clickspace Interactive Inc.join in the EOModeler.
Suite L100, 239 - 10th Ave. SE
Calgary, AB T2G 0V9