u don't have to have both sides of a relationship represented in your java
objects.  for example we have a many-to-many defined in the database.
however only one of the two java classes involved contains a collection of
the other.

we also have one-to-many relationships where we have done the opposite to
your question.  the child contains a reference to the parent, but the parent
doesn't contain the collection of children.

brad

-----Original Message-----
From: Robert Ollila [mailto:[EMAIL PROTECTED]]
Sent: Friday, 30 November 2001 1:41 AM
To: [EMAIL PROTECTED]
Subject: [castor-dev] JDO class design constrained by RDBMS relational
paradigm


Hi all,

I have been looking at the JDO "Product" example and I think I am concluding
some significant drawbacks.

In the example we have the top level "Product" class which contains a
collection of "ProductDetail" objects.  In order to model this containment
in the RDBMS the ProductDetail class must contain a reference to the Product
class which contains it.  If we were just using the Java object without
concern for persistance, we would not need to hold a "parent" reference in
each of the collected objects.  This seems like a significant drawback,
especially if you are trying to persist existing classes which are not
modelled this way.

Is there another way to establish the one-to-many relationship in the RDBMS
without changing existing classes which do not include references to the
classes which contain them?  In other words if the example ProductDetail
class did not contain a Product reference, how would we map the one-to-many
relationship?

thanks,

Bob.

======================================
Robert Ollila
Software Engineer
Vina Technologies
25 Manchester Street
Merrimack, NH 03054
603-589-0669
======================================

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