ForeignKey
- Implemented Interfaces:
Annotation
Specifies the handling of foreign key constraints when schema generation is in effect. If this annotation is not specified, a default foreign key strategy is selected by the persistence provider.
The ConstraintMode value is used to specify whether foreign key constraints should be generated.
The syntax used in the ForeignKey.foreignKeyDefinition element should follow the SQL syntax used by the target database for foreign key constraint creation. For example, it might be similar to the following:
FOREIGN KEY ( <COLUMN expression> {, <COLUMN expression>} ... ) REFERENCES <TABLE identifier> [ (<COLUMN expression> {, <COLUMN expression>} ... ) ] [ ON UPDATE <referential action> ] [ ON DELETE <referential action> ]
When the ConstraintMode value is CONSTRAINT, but the ForeignKey.foreignKeyDefinition element is not specified, the provider will generate foreign key constraints whose update and delete actions it determines most appropriate for the join column(s) to which the foreign key annotation is applied.
- See Also:
- JoinColumn
- JoinColumns
- MapKeyJoinColumn
- MapKeyJoinColumns
- PrimaryKeyJoinColumn
- JoinTable
- CollectionTable
- SecondaryTable
- AssociationOverride
- JoinColumns
- Since:
- JPA 2.1
Public Annotation Attributes
String foreignKeyDefinition default ""
- Since:
- JPA 2.1
String name default ""
Defaults to a provider-generated name.
- Since:
- JPA 2.1
String options default ""
May not be used in conjunction with ForeignKey.foreignKeyDefinition.
- Since:
- JPA 3.2
- ConstraintMode.CONSTRAINT specifies that the persistence provider must generate a foreign key constraint. If the ForeignKey.foreignKeyDefinition element is not specified, the provider will generate a constraint whose update and delete actions it determines most appropriate for the join column or columns to which the foreign key annotation is applied.
- ConstraintMode.NO_CONSTRAINT specifies that no constraint should be generated.
- ConstraintMode.PROVIDER_DEFAULT selects the default behavior of the provider, which may or may not result in generation of a constraint.
- Since:
- JPA 2.1