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hibernatejpaannotationssequence-generators
Ayub Malik
Ayub Malik

Reputation: 2578

Hibernate @SequenceGenerator not global

I have two entity classes which use generated values

@Entity
@SequenceGenerator(allocationSize = 1, initialValue = 1000, name = "idgen")
public class Ent1 {
    @Id
    @GeneratedValue(generator = "idgen")
    private Long id;

    ...
}

@Entity
public class Ent2 {
    @Id
    @GeneratedValue(generator = "idgen")
    private Long id;

    ...
}

The problem is that if don't put the line

@SequenceGenerator(allocationSize = 1, initialValue = 1000, name = "idgen")

on both entities I get an error:

Caused by: org.hibernate.AnnotationException: Unknown Id.generator: idgen

But the JPA spec says that the scope of the @SequenceGenerator is 'global' and can be reused across entities.

What am I missing?

Upvotes: 5

Views: 2304

Answers (4)

Christian Beikov
Christian Beikov

Reputation: 16452

In the past, Hibernate scoped the sequences per entity and then came JPA saying that this should be global, so in order to allow both, a setting was introduced to control this. You can enable global scoping by setting hibernate.jpa.compliance.global_id_generators to true. Also see the documentation about the details: https://docs.jboss.org/hibernate/orm/5.5/userguide/html_single/Hibernate_User_Guide.html#configurations-jpa-compliance

Upvotes: 2

ExploreEv
ExploreEv

Reputation: 895

copy 

@SequenceGenerator(allocationSize = 1, initialValue = 1000, name = "idgen")

to Ent2 should work,
you can refer https://www.logicbig.com/tutorials/java-ee-tutorial/jpa/seq-generator.html for more details

Upvotes: 1

Jidehem
Jidehem

Reputation: 1085

The following part of the spec is indeed strange to me.

The scope of the generator name is global to the persistence unit (across all generator types).

I would interpret it as you do: a generator can be specified at one location and reused anywhere on the same persistence unit. It's as if the current Hibernate implementation did not take this sentence into account.

Is there any JPA/Hibernate specification specialist that could help interpreting this sentence ?

Upvotes: 0

neildo
neildo

Reputation: 2386

This seems to be a bug in the Hibernate JPA implementation because it works how you expect with EclipseLink JPA Implementation (I tested both). With Hibernate, it only worked if I declared the SequenceGenerator at the application level using an orm.xml (assuming you are using JPA EntityManager). If you don't already have an orm.xml, it goes next to your persistence.xml.

Here's an example of declaring the sequence-generator in orm.xml:

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings
  xmlns="http://java.sun.com/xml/ns/persistence/orm"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
  version="2.0">

  <sequence-generator name="idgen" allocation-size="1" initial-value="1000" />

</entity-mappings>

Then you don't have to declare the SequenceGenerator in each class.

Upvotes: 1

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