Choosing mapping tables at runtime

jens.askengren@resfeber.s · **Joined:** Tue Feb 01, 2005 6:52 am **Posts:** 2

Hello!

Is it possible to to select the table used to map a specified class at runtime? Consider this example:

A legacy database contains a number of tables for customer of different countries. The columns in the tables are identical, only the table name differs:

Code:

customer_uk
customer_de
customer_fr

and so on. I would like to use the same class to map their content:

Code:

from Customer c where c.id =: customerId

rather than

Code:

from CustomerUk c where c.id =: customerId

is this possible?

I've tried to use a combination of multiple SessionFactories and NamingStrategies to accomplish this, but it fails. (Seems like only the first instance created loads the mapping).

max · **Posted:** Tue Feb 01, 2005 12:17 pm

look into Hibernate 3 and entityname.

max · **Posted:** Tue Feb 01, 2005 12:18 pm

and btw. how would you let hibernate decide which table to go into first ?

if only one table is "active" per sessionfactory then you could just e.g. use a NamingStrategy instance to control which table is used when.

jens.askengren@resfeber.s · **Joined:** Tue Feb 01, 2005 6:52 am **Posts:** 2

Quote:

if only one table is "active" per sessionfactory then you could just e.g. use a NamingStrategy instance to control which table is used when.

This indeed works. Making it work under JBoss required some really dirty code though.

It would be very flexible if the NamingStrategy could be set for each query:

Code:

session.createQuery(...)
  .setNamingStrategy(new CountryTableNamingStrategy("uk"))
  .list()

But that would ofcourse introduce some overhead.