Wanted to start a follow up discussion to the conversation we had at the
IRC meeting on 6/13 with regards to changing the way we process mapping
information to follow dependencies in the various types of information.
What we do currently (in the metamodel code) is essentially the same as
the legacy code. That is to say we process through a mapping source in
full and then move on to the next one, saving off "second passes"
whenever we encounter information on which we have to wait. The second
passes in the new metamodel code are isolated I guess (so far) to
org.hibernate.metamodel.source.internal.EntityReferenceResolver
What I proposed instead is quite different, more like what I did for the
rest of the MetadataImpl constructor code in terms of defining
dependencies and processing stuff in an order that makes sure to avoid
the need for second passes.
Here is the initial swab at the levels of information:
1) entity - basic entity information such as name, hierarchy
2) identifiers - normal identifiers could almost be handled in the first
level. key-many-to-one still needs some form of delayed queuing.
3) secondary tables
4) attributes
5) associations
The dependencies flow downward; (2) depends on (1); (3) depends on (2); etc.
I liked handling (3) secondary tables separately because they basically
expand the possible set of columns available for (4) and (5).
--
Steve Ebersole <steve(a)hibernate.org>
http://hibernate.org