Hi, I have a system which is using JBoss an hibernate, with EJB.3.0. My system can be deployed using diffent database systems, e.g. PostgreSQL, Hypersonic, Oracle, MySql, as I have no database specific code. We use general EJB QL for our queries. So lets say I deploy my application using Mysql. The datamodel is generated in the Mysql DB and everything works fine. Now, after a while I whish to change to say Hypersonic DB or PostgreSQL. I want to keep the allready persisted data. But I have a problem as e.g. enums are translated to different datatypes for the different DBMS. I cannot simply e.g. do an SQL export / import between the different DBMSs, as the O/R mappings will fail. So what I would need is some way to migrate the data through the EJB context, first populating the existing enitities, and do a new O/R mapping to the new DBMS. It there such a tool available? Surely other people must have faced this issue before me? Thanks for your response. -R View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4088297#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...