[hibernate-dev] Object/Relational mapping XML processing moving forward

[Steve Ebersole]

Reference :
https://hibernate.atlassian.net/browse/HHH-8893
https://hibernate.atlassian.net/browse/HHH-8894

I wanted to start a discussion around some planned changes relating to 
processing XML mapping files.  The 2 issues above cover the bulk of the 
intent:
1) move to a single format for expressing object/relational mapping in 
XML, based on the JPA ORM XSD
2) combine that with transformations for numerous known formats to a 
definitive format for processing.

The basic idea here is to have just one XML format that we actually 
process as input (StAX+JAXB).  It would be a derivative of the latest 
JPA ORM XSD ("extended" for Hibernate-specifics).  We would still accept 
numerous other forms (hbm.dtd, "straight" orm.xsd versions 1.0, 2.0, 
2.1) and transform them to the "extended" schema.  This transformation 
would be available on-the-fly as well as via a build-time task.

This opens up the question of exactly how we want to mix the 
Hibernate-specifics in with the JPA entity-mappings schema types. For 
example we might want to take this opportunity to "clean up" the things 
we expose via XML, or unify them.  For now, I'd like to just make this 
an open call for suggestions of things people would like to see changed 
in XML mappings.