Hi Tony!
Thanks for your quick answer. But I'm still not convinced. Besides many to
many relation there is, as I see it, no need for a third table (with this
principle, a many-to-many relation would result in five tables as you
translate it to two many-to-one, or?). Let me exemplify my conception with
order and orderlines (one to many):
OO-model
Order:
public abstract void setOrderId(String orderId);
public abstract String getOrderId();
public abstract Collection getOrderLines(); // A collection with references to
orderlines
OrderLines:
public abstract void setOrderLineId(String orderLineId);
public abstract String getOrderLineId();
An ER-model of the same relation would according to my conception be as follows (if
you disregard the mapping):
Order:
OrderId (PK)
OrderLines
OrderLineId (PK)
OrderId (FK) // Foreign key to order.
In this case there is no redundancy. Or am I totally lost?
Regards, Theis.
