231 words
javax.persistence.GeneratedValue - JPA annotation
javax.persistence
Annotation GeneratedValue
- Target:
- Fields (including property get methods)
Provides for the specification of generation strategies for the
values of primary keys.
The GeneratedValue annotation
may be applied to a primary key property or field of an entity or
mapped superclass in conjunction with the Id annotation.
The use of the GeneratedValue annotation is only
required to be supported for simple primary keys. Use of the
GeneratedValue annotation is not supported for derived
primary keys.
Example 1:
@Id @GeneratedValue(strategy=SEQUENCE, generator="CUST_SEQ") @Column(name="CUST_ID") public Long getId() { return id; }
Example 2:
@Id @GeneratedValue(strategy=TABLE, generator="CUST_GEN") @Column(name="CUST_ID") Long id;
- Since:
- JPA 1.0
- See Also:
IdTableGeneratorSequenceGenerator
Learn how to define and use automatic value generation in Chapter 2 of the ObjectDB/JPA manual.
String generator
(Optional) The name of the primary key generator
to use as specified in the
SequenceGenerator
or TableGenerator annotation.
Defaults to the id generator supplied by persistence provider.
- Default value:
- ""
- Since:
- JPA 1.0
(Optional) The primary key generation strategy
that the persistence provider must use to
generate the annotated entity primary key.
- Default value:
- javax.persistence.GenerationType.AUTO
- Since:
- JPA 1.0
This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.