/*
* Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution. The Eclipse Public License is available
* at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
* is available at http://www.eclipse.org/org/documents/edl-v10.php.
*/
package javax.persistence;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import static javax.persistence.FetchType.LAZY;
Defines a many-valued association with one-to-many multiplicity.
If the collection is defined using generics to specify the element type, the associated target entity type
need not be specified; otherwise the target entity class must be specified. If the relationship is
bidirectional, the mappedBy element must be used to specify the relationship field or
property of the entity that is the owner of the relationship.
The OneToMany annotation may be used within an embeddable class contained within an entity
class to specify a relationship to a collection of entities. If the relationship is bidirectional, the
mappedBy element must be used to specify the relationship field or property of the entity
that is the owner of the relationship. When the collection is a java.util.Map, the
cascade element and the orphanRemoval element apply to the map value.
Example 1: One-to-Many association using generics
// In Customer class:
@OneToMany(cascade=ALL, mappedBy="customer")
public Set<Order> getOrders() { return orders; }
In Order class:
@ManyToOne
@JoinColumn(name="CUST_ID", nullable=false)
public Customer getCustomer() { return customer; }
Example 2: One-to-Many association without using generics
// In Customer class:
@OneToMany(targetEntity=com.acme.Order.class, cascade=ALL,
mappedBy="customer")
public Set getOrders() { return orders; }
// In Order class:
@ManyToOne
@JoinColumn(name="CUST_ID", nullable=false)
public Customer getCustomer() { return customer; }
Example 3: Unidirectional One-to-Many association using a foreign key mapping
// In Customer class:
@OneToMany(orphanRemoval=true)
@JoinColumn(name="CUST_ID") // join column is in table for Order
public Set<Order> getOrders() {return orders;}
Since: Java Persistence 1.0
/**
* Defines a many-valued association with one-to-many multiplicity.
* <p>
* If the collection is defined using generics to specify the element type, the associated target entity type
* need not be specified; otherwise the target entity class must be specified. If the relationship is
* bidirectional, the <code> mappedBy</code> element must be used to specify the relationship field or
* property of the entity that is the owner of the relationship.
* <p>
* The <code>OneToMany</code> annotation may be used within an embeddable class contained within an entity
* class to specify a relationship to a collection of entities. If the relationship is bidirectional, the
* <code> mappedBy</code> element must be used to specify the relationship field or property of the entity
* that is the owner of the relationship. When the collection is a <code>java.util.Map</code>, the
* <code>cascade</code> element and the <code>orphanRemoval</code> element apply to the map value.
* <p>
* <pre>
*
* Example 1: One-to-Many association using generics
*
* // In Customer class:
*
* @OneToMany(cascade=ALL, mappedBy="customer")
* public Set<Order> getOrders() { return orders; }
*
* In Order class:
*
* @ManyToOne
* @JoinColumn(name="CUST_ID", nullable=false)
* public Customer getCustomer() { return customer; }
*
*
* Example 2: One-to-Many association without using generics
*
* // In Customer class:
*
* @OneToMany(targetEntity=com.acme.Order.class, cascade=ALL,
* mappedBy="customer")
* public Set getOrders() { return orders; }
*
* // In Order class:
*
* @ManyToOne
* @JoinColumn(name="CUST_ID", nullable=false)
* public Customer getCustomer() { return customer; }
*
*
* Example 3: Unidirectional One-to-Many association using a foreign key mapping
*
* // In Customer class:
*
* @OneToMany(orphanRemoval=true)
* @JoinColumn(name="CUST_ID") // join column is in table for Order
* public Set<Order> getOrders() {return orders;}
*
* </pre>
*
* @since Java Persistence 1.0
*/
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface OneToMany {
(Optional) The entity class that is the target of the association. Optional only if the collection
property is defined using Java generics. Must be specified otherwise.
Defaults to the parameterized type of the collection when defined using generics.
Returns: target entity
/**
* (Optional) The entity class that is the target of the association. Optional only if the collection
* property is defined using Java generics. Must be specified otherwise.
* <p>
* Defaults to the parameterized type of the collection when defined using generics.
*
* @return target entity
*/
Class targetEntity() default void.class;
(Optional) The operations that must be cascaded to the target of the association.
Defaults to no operations being cascaded.
When the target collection is a java.util.Map, the cascade element
applies to the map value.
Returns: cascade type
/**
* (Optional) The operations that must be cascaded to the target of the association.
* <p>
* Defaults to no operations being cascaded.
* <p>
* When the target collection is a {@link java.util.Map java.util.Map}, the <code>cascade</code> element
* applies to the map value.
*
* @return cascade type
*/
CascadeType[] cascade() default {};
(Optional) Whether the association should be lazily loaded or must be eagerly fetched. The EAGER
strategy is a requirement on the persistence provider runtime that the associated entities must be
eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime.
Returns: The fetch type
/**
* (Optional) Whether the association should be lazily loaded or must be eagerly fetched. The EAGER
* strategy is a requirement on the persistence provider runtime that the associated entities must be
* eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime.
*
* @return The fetch type
*/
FetchType fetch() default LAZY;
The field that owns the relationship. Required unless the relationship is unidirectional.
Returns: mappedby
/**
* The field that owns the relationship. Required unless the relationship is unidirectional.
*
* @return mappedby
*/
String mappedBy() default "";
(Optional) Whether to apply the remove operation to entities that have been removed from the
relationship and to cascade the remove operation to those entities.
Returns: whether to remove orphans Since: Java Persistence 2.0
/**
* (Optional) Whether to apply the remove operation to entities that have been removed from the
* relationship and to cascade the remove operation to those entities.
*
* @return whether to remove orphans
* @since Java Persistence 2.0
*/
boolean orphanRemoval() default false;
}