I am working on our project migration from hibernate 1.2 to hibernate 2.1.4. In old mapping files we used <generator class="vm.long"/> I have updated generator to <generator class="increment"/> and now when I try to create a new object ant to save to the database I get:

java.sql.BatchUpdateException: Invalid argument value: Duplicate entry '70979778677178481' for key 1

This id was created by hibernate 1.2 version and the new generator generates duplicate ids.

Does anybody know how to solve the problem ? I do not want to use another id generator (for example identity) because this will involve modification of the database schema (we use mySQL database).

Thanks in advance

consider building you own generator, it'll be the safiest way.

I found what the problem occurs because of mySQL. IncrementGenerator retrieves max id and increments the max id by 1. The problem occurs because mySQL's max function returns an id which does not exist in the database and hibernate generates an id that already exists in the db. I use mySQL version 3.23.49. I have tested my app with mySQL 4.1.1 and the problem disappeared.