Postgresql UUID supported by Hibernate?

Question

I can't get Hibernate working with java.util.UUID for PostgreSQL.

Here is the mapping using javax.persistence.* annotations:

private UUID itemUuid;

@Column(name="item_uuid",columnDefinition="uuid NOT NULL")
public UUID getItemUuid() {
    return itemUuid;
}

public void setItemUuid(UUID itemUuid) {
    this.itemUuid = itemUuid;
}

When persisting a transient object I get a SQLGrammarException:

column "item_uuid" is of type uuid but expression is of type bytea at character 149

PostgreSQL version is 8.4.4
JDBC driver - 8.4.4-702 (also tried 9.0 - same thing)
Hibernate version is 3.6, main configuration properties:

<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.url">jdbc:postgresql://192.168.1.1/db_test</property>

Answer 1

This can be solved by adding the following annotation to the UUID:

import org.hibernate.annotations.Type;
...
@Type(type="pg-uuid")
private java.util.UUID itemUuid;

As to why Hibernate doesn't just make this the default setting, I couldn't tell you...

UPDATE: There still seem to be issues using the createNativeQuery method to open objects that have UUID fields. Fortunately, the createQuery method so far has worked fine for me.

Answer 2

Now you can also use the UUID class provided by java.util.UUID which gets mapped to uuid datatype of Postgres by Hibernate without any conversions required while reading/writing from the database.

  @Id
  @GeneratedValue
  private UUID id;

The generated value is auto by default this lets your JVM define the UUID. This also allows hibernate to use the batch insert optimisation.

You can configure the database to set the UUID value. More information can be found here https://vladmihalcea.com/uuid-identifier-jpa-hibernate/