休眠：更新表生成器

Question

Is there a way to tell Hibernate to first check if the current primary key generated by a Table Generator is usable or outdated?

I have an application which uses hibernate to create new entries in several tables in my database, but sometimes these generated values are outdated and already used. This happens because this database is used by quite a few applications and scripts, and some of these use the "select MAX(ID)+1"-Keygeneration"strategy". It is not really an option to change all other components to use the table generator (although it would solve the problem), so I have to make sure that the values I get from the table generator are really usable.

Is there any way to tell Hibernate to check the validity of the generated values before it tries to insert a new record into the database (and throw a ConstraintViolationException)? Or, alternatively, is there a way to manually update the generator tables before hibernate uses them to generate new Ids?

The obvious way would be to run a native query like UPDATE pk_generator SET value=(SELECT MAX(ID)+1 from members) WHERE column='members'

Answer 1

When you save a object with saveOrUpdate() the objects id field will get updated with the auto generated id if it was a create operation. So that it will never conflict with id which was already generated and used.