Module jakarta.persistence

Package jakarta.persistence

Annotation Interface IdClass

@Target(TYPE)
@Retention(RUNTIME)
public @interface IdClass

Specifies a composite primary key type whose fields or properties map to the identifier 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 Annotation.equals(java.lang.Object) and 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) {}

Since:

1.0

See Also:

• EmbeddedId

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
Class<?>	value	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.

Element Details

value

Class<?> value

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.