I have a situation where I need to add an uniqueness constraint to an existing table column. I updated the hbm file and added the unique-key in the right place, then executed a query to the table. The table does not make the adjustment.

The only way I can get the table to accept the uniqueness constraint is by dropping it and re-create from scratch.

And I have hibernate.hbm2ddl.auto=update set.

Is there a way to make the schema update without dropping the table?