This guide discusses migration from Hibernate ORM version 5.0 to version 5.1. For migration from earlier versions, see any other pertinent migration guides as well.

Oracle12cDialect maps byte[] and Byte[] to BLOB

Previous versions of Hibernate have mapped byte[] and Byte[] to Oracle’s LONG RAW data type (via the JDBC LONGVARBINARY type). Oracle have deprecated the LONG RAW data type for many releases - possibly as far back as 8i. Therefore it was decided to start having Hibernate map byte[] and Byte[] to BLOB for Oracle.

However, in the interest of backwards compatibility and not breaking existing applications it was also decided to limit this change to just the Oracle12cDialect. So starting in 5.1 applications using Oracle12cDialect and implicitly mapping byte[] and Byte[] values will start seeing those handled as BLOB data rather than LONG RAW data. For existing applications that want to continue to use Oracle12cDialect and still continue to implicitly map byte[] and Byte[] attributes to LONG RAW, there is a new configuration setting you can use to enable that: hibernate.dialect.oracle.prefer_longvarbinary, which is false by default (map to BLOB).

Changes to schema management tooling

The changes mainly focused on:

  • Unifying handling of hbm2ddl.auto and Hibernate’s JPA schema-generation support.

  • Removing JDBC concerns from the SPI to facilitate true replacement (for OGM)

These changes will only be a migration concern for applications directly using any of the following classes:

  • org.hibernate.tool.hbm2ddl.SchemaExport

  • org.hibernate.tool.hbm2ddl.SchemaUpdate

  • org.hibernate.tool.hbm2ddl.SchemaValidator

  • org.hibernate.tool.schema.spi.SchemaManagementTool or any of its delegates