Hi, I don't know if this is the right post for this question or if this issue has already been answered. I've just been working with hibernate persistence using embedded Derby and MySQL. In derby, when a table is created, it does not include indexes and unique constraints. so @Column( unique=true ) does not work and so does @uniqueConstraint. I've tested the same entity using MySQL and it does so perfectly. Is embedded derby not yet fully supported by hibernate? I've plan to include persistence in client side and any changes I would do to the entity would be automatically recreated in the client without manual intervention, i.e. including indexes. If this has been answered, pls. redirect me to the posts. Thanks. Regards, Elmo View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3995984#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...