@Target({METHOD,FIELD}) @Retention(RUNTIME) public @interface EmbeddedId

Specifies that the annotated persistent field or property of an entity class or mapped superclass is the composite primary key of the entity. The type of the annotated field or property must be an embeddable type, and must be explicitly annotated Embeddable.

If a field or property of an entity class is annotated EmbeddedId, then no other field or property of the entity may be annotated Id or EmbeddedId, and the entity class must not declare an IdClass, except in the special case where the EmbeddedId represents the composite primary key of a parent entity in an entity with a derived identity represented as an IdClass.

The embedded primary key type must implement Annotation.equals(Object) and Annotation.hashCode(), defining value equality consistently with equality of the mapped primary key of the database table.

The AttributeOverride annotation may be used to override the column mappings declared within the embeddable class.

The MapsId annotation may be used in conjunction with the EmbeddedId annotation to declare a derived primary key.

If the entity has a derived primary key, the AttributeOverride annotation may only be used to override those attributes of the embedded id that do not correspond to the relationship to the parent entity.

Relationship mappings defined within an embedded primary key type are not supported.

Example 1:

@Entity
public class Employee {
    @EmbeddedId
    protected EmployeePK empPK;
...
}

public record EmployeePK(String empName, Date birthDay) {}

Example 2:

@Embeddable
public class PaycheckId {
    int period;
    EmployeeId empPK;   // corresponds to primary key type of Employee
}

@Entity
public class Paycheck {
    // default column name for 'period' attribute is overridden
    @AttributeOverride(name = "period", column = @Column(name = "pay_period"))
    @EmbeddedId
    PaycheckId id;
    ...
    @MapsId("empPK")
    @ManyToOne
    Employee emp;
}

Since:

1.0

See Also:

Annotation Interface EmbeddedId