javax.persistence

Annotation Type PrimaryKeyJoinColumn

@Target(value={TYPE,METHOD,FIELD})
@Retention(value=RUNTIME)
public @interface PrimaryKeyJoinColumn

Specifies a primary key column that is used as a foreign key to join to another table.

It is used to join the primary table of an entity subclass in the JOINED mapping strategy to the primary table of its superclass; it is used within a SecondaryTable annotation to join a secondary table to a primary table; and it may be used in a OneToOne mapping in which the primary key of the referencing entity is used as a foreign key to the referenced entity.

If no PrimaryKeyJoinColumn annotation is specified for a subclass in the JOINED mapping strategy, the foreign key columns are assumed to have the same names as the primary key columns of the primary table of the superclass.

    Example: Customer and ValuedCustomer subclass

    @Entity
    @Table(name="CUST")
    @Inheritance(strategy=JOINED)
    @DiscriminatorValue("CUST")
    public class Customer { ... }
    
    @Entity
    @Table(name="VCUST")
    @DiscriminatorValue("VCUST")
    @PrimaryKeyJoinColumn(name="CUST_ID")
    public class ValuedCustomer extends Customer { ... }
 

See Also:

SecondaryTable, Inheritance, OneToOne, ForeignKey

Since:

Java Persistence 1.0

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
java.lang.String	columnDefinition (Optional) The SQL fragment that is used when generating the DDL for the column.
ForeignKey	foreignKey (Optional) Used to specify or control the generation of a foreign key constraint for the primary key join column when table generation is in effect.
java.lang.String	name (Optional) The name of the primary key column of the current table.
java.lang.String	referencedColumnName (Optional) The name of the primary key column of the table being joined to.

Element Detail

name

public abstract java.lang.String name

(Optional) The name of the primary key column of the current table.

Defaults to the same name as the primary key column of the primary table of the superclass (JOINED mapping strategy); the same name as the primary key column of the primary table (SecondaryTable mapping); or the same name as the primary key column for the table for the referencing entity (OneToOne mapping).

Default:

""

referencedColumnName

public abstract java.lang.String referencedColumnName

(Optional) The name of the primary key column of the table being joined to.

Defaults to the same name as the primary key column of the primary table of the superclass (JOINED mapping strategy); the same name as the primary key column of the primary table (SecondaryTable mapping); or the same name as the primary key column for the table for the referencing entity (OneToOne mapping).

Default:

""

columnDefinition

public abstract java.lang.String columnDefinition

(Optional) The SQL fragment that is used when generating the DDL for the column. This should not be specified for a OneToOne primary key association.

Defaults to the generated SQL to create a column of the inferred type.

Default:

""

foreignKey

public abstract ForeignKey foreignKey

(Optional) Used to specify or control the generation of a foreign key constraint for the primary key join column when table generation is in effect. If this element is not specified, the persistence provider's default foreign key strategy will apply.

Since:

Java Persistence 2.1

Default:

@javax.persistence.ForeignKey(javax.persistence.ConstraintMode.PROVIDER_DEFAULT)