MapKeyJoinColumns (Java EE 8)

```
@Target({METHOD,FIELD})
@Retention(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
Modifier and Type Required Element Description

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

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