JPA Annotation

IdClass

Target: TYPE
Implemented Interfaces:
Annotation
Specifies a composite primary key type whose fields or properties map to the plain fields or properties of the annotated entity class.

The specified primary key type must:

  • be a non-abstract regular Java class, or a Java record type,
  • have a public or protected constructor with no parameters, unless it is a record type, and
  • implement equals and hashCode, defining value equality consistently with equality of the mapped primary key of the database table.

The primary key fields of the entity must be annotated Id, and the specified primary key type must have fields or properties with matching names and types. The mapping of fields or properties of the entity to fields or properties of the primary key class is implicit. The primary key type does not itself need to be annotated.

Example:

 {@snippet :
 @IdClass(EmployeePK.class)
 @Entity
 public class Employee {
See Also:
EmbeddedId
Since:
JPA 1.0

Public Annotation Attributes

Class<?> value default null
The primary key class, which must declare fields or properties with names and types that match the Id fields and properties of the annotated entity class.
Since:
JPA 1.0