Module jakarta.persistence

Package jakarta.persistence

Annotation Interface ForeignKey

@Target({})
@Retention(RUNTIME)
public @interface ForeignKey

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 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 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.

Since:

2.1

See Also:

• JoinColumn
• JoinColumns
• MapKeyJoinColumn
• MapKeyJoinColumns
• PrimaryKeyJoinColumn
• JoinTable
• CollectionTable
• SecondaryTable
• AssociationOverride

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
String	foreignKeyDefinition	(Optional) The foreign key constraint definition.
String	name	(Optional) The name of the foreign key constraint.
String	options	(Optional) A SQL fragment appended to the generated DDL which creates this foreign key.
ConstraintMode	value	(Optional) Used to specify whether a foreign key constraint should be generated when schema generation is in effect.

Element Details

name

String name

(Optional) The name of the foreign key constraint.

Defaults to a provider-generated name.

Default:

""

value

ConstraintMode value

(Optional) Used to specify whether a foreign key constraint should be generated when schema generation is in effect.

• ConstraintMode.CONSTRAINT specifies that the persistence provider must generate a foreign key constraint. If the 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.

Default:

CONSTRAINT

foreignKeyDefinition

String foreignKeyDefinition

(Optional) The foreign key constraint definition.

Default:

""

options

String options

(Optional) A SQL fragment appended to the generated DDL which creates this foreign key. May not be used in conjunction with foreignKeyDefinition().

Since:

3.2

Default:

""