Hello,

Using Hibernate in Update mode generates “alter table” on columns of type blob/clob which seems to be forbidden in Oracle. Each time the alter table command is sent on these columns, Oracle responds with an error of type ORA-22859.

From the test case I made, the corresponding exception looks like this :

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "
alter table LobModel
modify blob blob" via JDBC [ORA-22859: modification non valide des colonnes

My test case is available at : https://github.com/brivalin/hibernate-test-case-templates

To reproduce the problem you have to :

1. Modify the persistence.xml to point to your own Oracle database
2. Run it once to generate the schema
3. Run it a second time to throw the ORA-22859 error

The original Discussion is available here : https://discourse.hibernate.org/t/schemamigrator-wants-to-alter-my-columns/7697/13