MapsId (Jakarta Persistence API documentation)

```
@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface MapsId
```
Designates a ManyToOne or OneToOne relationship attribute that provides the mapping for an EmbeddedId primary key, an attribute within an EmbeddedId primary key, or a simple primary key of the parent entity.
The value() element specifies the attribute within a composite key to which the relationship attribute corresponds. If the primary key of the entity is of the same Java type as the primary key of the entity referenced by the relationship, the value attribute is not specified.
In this example, the parent entity has simple primary key: {@snippet :

Since:

2.0

- Optional Element Summary
  
  Optional Elements
  Modifier and Type Optional Element Description
  
  String value
  (Optional) The name of the attribute within the composite key to which the relationship attribute corresponds.

- Element Detail
  - value
```
String value
```
    (Optional) The name of the attribute within the composite key to which the relationship attribute corresponds. If not explicitly specified, the relationship maps the primary key of the entity.
    
    Default:
    
    ""