javax.persistence

## Annotation Type MapKeyJoinColumns

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

Supports composite map keys that reference entities.

The `MapKeyJoinColumns` annotation groups `MapKeyJoinColumn` annotations. When the `MapKeyJoinColumns` annotation is used, both the `name` and the `referencedColumnName` elements must be specified in each of the grouped `MapKeyJoinColumn` annotations.

Since:
  Java Persistence 2.0
See Also:
  `MapKeyJoinColumn`, `ForeignKey`

### Required Element Summary

Required Elements
`MapKeyJoinColumn[]` `value` (Required) The map key join columns that are used to map to the entity that is the map key.

### Optional Element Summary

Optional Elements
`ForeignKey` `foreignKey` (Optional) Used to specify or control the generation of a foreign key constraint when table generation is in effect.

### Element Detail

#### value

    public abstract MapKeyJoinColumn[] value

(Required) The map key join columns that are used to map to the entity that is the map key.

#### foreignKey

    public abstract ForeignKey foreignKey

(Optional) Used to specify or control the generation of a foreign key constraint when table generation is in effect. If both this element and the `foreignKey` element of any of the `MapKeyJoinColumn` elements are specified, the behavior is undefined. If no foreign key annotation element is specified in either location, the persistence provider's default foreign key strategy will apply.

Since:
  Java Persistence 2.1

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