jakarta.persistence.IdClass

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 Annotation.java.lang.annotation.Annotation/equals(Object) and Annotation.java.lang.annotation.Annotation/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:

 @IdClass(EmployeePK.class)
 @Entity
 public class Employee {
     @Id
     String empName;
     @Id
     Date birthDay;
     ...
 }

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

See Also:

EmbeddedId

Since:

Jakarta Persistence (JPA) 1.0