How to define shared sequence generator in Hibernate / JPA?

Question

We import data to DB by external process and also allow to modify/add data inside app. To avoid UUIDs and simplify code single Oracle DB sequence HIBERNATE_SEQUENCE is used in external process and I need to use it for affected entities.

My naive definitions on each entity are failed:

@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "HIBERNATE_SEQUENCE")
@SequenceGenerator(name = "HIBERNATE_SEQUENCE", sequenceName = "HIBERNATE_SEQUENCE")

with:

HibernateException: Multiple references to database sequence [hibernate_sequence] were encountered attempting toset conflicting values for 'increment size'.

Defining only on singe entity:

@SequenceGenerator(name = "HIBERNATE_SEQUENCE", sequenceName = "HIBERNATE_SEQUENCE")

(and @GeneratedValue on others) causes:

org.hibernate.AnnotationException: Unknown Id.generator: HIBERNATE_SEQUENCE

How I can use single sequence on different entities?

UPDATE Also I had:

org.hibernate.HibernateException: Multiple references to database sequence [hibernate_sequence] were encountered attempting toset conflicting values for 'increment size'. Found [1] and [50]

at some stage as previously I defined physical sequence as:

create sequence HIBERNATE_SEQUENCE
minvalue 1
maxvalue 9999999999999999999999999999
start with 1
increment by 1;

and default hibernate step is 50...

gavenkoa · Accepted Answer · 2017-07-26 16:39:10Z

1

Looks like stupid solution of using separate Hibernate logical names works:

@Entity
public class Cat {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "Cat_seq")
    @SequenceGenerator(name = "Cat_seq", sequenceName = "HIBERNATE_SEQUENCE", allocationSize = 1)
    Long id;
}

@Entity
public class Dog {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "Dog_seq")
    @SequenceGenerator(name = "Dog_seq", sequenceName = "HIBERNATE_SEQUENCE", allocationSize = 1)
    Long id;
}

SequenceGenerator.sequenceName set physical sequence name which should correctly work as Hibernate can't make ay assumption on exclusive use of physical object in distributed environment which Oracle DB is...

allocationSize = 1 should be provided as default value is 50 which is different fro original physical sequence definition.

edited Jul 26, 2017 at 16:39

answered Jul 26, 2017 at 16:15

gavenkoa

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