jakarta.persistence.MapsId Maven / Gradle / Ivy
/*
* Copyright (c) 2008, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0,
* or the Eclipse Distribution License v. 1.0 which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
*/
// Contributors:
// Linda DeMichiel - 2.1
// Linda DeMichiel - 2.0
package jakarta.persistence;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Designates a ManyToOne or
* OneToOne relationship attribute that provides the
* mapping for an {@link 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 entity's primary key is of the same
* Java type as the primary key of the entity referenced by the
* relationship, the value attribute is not specified.
*
*
* Example:
*
* // parent entity has simple primary key
*
* @Entity
* public class Employee {
* @Id long empId;
* String name;
* ...
* }
*
* // dependent entity uses EmbeddedId for composite key
*
* @Embeddable
* public class DependentId {
* String name;
* long empid; // corresponds to primary key type of Employee
* }
*
* @Entity
* public class Dependent {
* @EmbeddedId DependentId id;
* ...
* @MapsId("empid") // maps the empid attribute of embedded id
* @ManyToOne Employee emp;
* }
*
*
* @since 2.0
*/
@Target( { METHOD, FIELD })
@Retention(RUNTIME)
public @interface MapsId {
/**
* (Optional) The name of the attribute within the composite key
* to which the relationship attribute corresponds. If not
* supplied, the relationship maps the entity's primary
* key.
*/
String value() default ""; }