Sorry, I sent the last email using the wrong mail address.
Matthias
-----Original Message-----
From: Matthias Bohlen [mailto:[EMAIL PROTECTED]
Sent: Saturday, March 27, 2004 3:25 PM
To: '[EMAIL PROTECTED]'
Subject: Mapping subclasses in separate tables - how?
Hi, all,
with the Hibernate cartridge for AndroMDA (see www.andromda.org), we
generate POJOs which are mapped to a DB using Hibernate (no wonder). The
interesting thing is that we generate XDoclet tags and let XDoclet
generate the *.hbm.xml files.
We now have a sample program ("animal quiz" game) that guesses an animal
the user has in mind by asking questions to the user. Inside the
business tier, we build a decision tree made of three classes:
DecisionItem (the base class), Animal and Question (both subclasses of
DecisionItem). AndroMDA generates @hibernate.subclass tags in
Animal.java and Question.java.
Now, at the end of the generation process when XDoclet runs, it
generates *only one* file called DecisionItem.hbm.xml! There are no
Animal.hbm.xml and no Question.hbm.xml because those classes are mapped
as subclasses inside DecisionItem.hbm.xml.
As a result, the database contains *only one* table called DECISION_ITEM
with *all* the columns from DecisionItem, Animal, and Question. This is
not what we want. We want three tables DECISION_ITEM, ANIMAL and
QUESTION that have the columns from DecisionItem, (DecisionItem+Animal)
and (DecisionItem+Question), the latter two tables connected to the
first using a foreign key or using key identity.
Which XDoclet tags do we have to generate in order to get these three
tables?
Cheers...
Matthias
---
Matthias Bohlen
"Consulting that helps project teams to succeed..."
http://www.mbohlen.de/
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