Good evening,

I'm looking to design an extensible object model on top of hibernate, by this I mean the following:

I have an existing object model mapped with hibernate and POJOs.

I wish to have a number of "empty" colums in the database of various types, and each object in the domain model has a one-to-one to a loosly defined pojo class that is the parent of the dynamic classes, mapped onto the same table as the primary pojo class.

I'll then allow (via groovy) new classes at runtime. I wish to then map properties of these classes to existing columns in the database.

I can then use hql to do reporting, searching, etc against a normalized physical model. The extension classes will also be available to the classloader, such that they'll be visible in jsf el expressions / Freemarker templates etc.

I've spent a bit of time looking at the source for Configuration, Mapping, PersistentClass, Table, etc (org.hibernate.mapping.*), but I'm wondering if anyone has done something similar or has any pointers to ease the pain of doing what I'm working on.

I plan to store these groovy defined classes in the DB (or on the file system) such that at container/configuration reload I'll load the default object model and then modify it with my extensions.

I'm going to keep digging in the source and taking baby steps, but any thoughts or guidance are greatly appreciated.

thanks

I haven't done that so I don't know all the tips/tricks but maybe this will help you out.





I am not sure what are all the setters you need to call to add all the objects but I guess you should look at the mapping file and duplicate all the elements and attributes with setters.

I have the exact same question as stibrian, regarding how to build an extensible database schema using NHibernate.

For each extensible Entity, there are two database tables [Entity] and [Entity]Extension. These two tables are mapped 1-to-1. The first table [Entity] is known at design time, but the second table [Entity]Extension changes during runtime. It is also possible to add a new pair of [Entity] and [Entity]Extension during runtime.

Even though I can provide both the object classes and the hbm mapping files of both [Entity] and [Entity]Extension, the [Entity]Extension's schema will be modified by user during run-time.

How do I adjust NHibernate SessionFactory's class mapping of [Entity]Extension during run-time to reflect new changes?

How do I adjust initialized .NET Assembly Type of [Entity]Extension during run-time to cope with NHibernate SessionFactory?

It can be assumed that only addition of columns, or new types are allowed.

Will the use of multiple session factory help?

Will the use of multiple AppDomain help?

I have the exact same question as stibrian, regarding how to build an extensible database schema using NHibernate.

For each extensible Entity, there are two database tables [Entity] and [Entity]Extension. These two tables are mapped 1-to-1. The first table [Entity] is known at design time, but the second table [Entity]Extension changes during runtime. It is also possible to add a new pair of [Entity] and [Entity]Extension during runtime.

Even though I can provide both the object classes and the hbm mapping files of both [Entity] and [Entity]Extension, the [Entity]Extension's schema will be modified by user during run-time.

How do I adjust NHibernate SessionFactory's class mapping of [Entity]Extension during run-time to reflect new changes?

How do I adjust initialized .NET Assembly Type of [Entity]Extension during run-time to cope with NHibernate SessionFactory?

It can be assumed that only addition of columns, or new types are allowed.

Will the use of multiple session factory help?

Will the use of multiple AppDomain help?