File Doc Category Size Date Package
OneToMany.java API Doc Glassfish v2 API 4642 Fri May 04 22:34:06 BST 2007 javax.persistence

OneToMany

public class OneToMany

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.


Example 1: One-to-Many association using generics

In Customer class:

@OneToMany(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 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; }

since: Java Persistence 1.0

Fields Summary
Constructors Summary
Methods Summary
javax.persistence.CascadeType[] cascade()
(Optional) The operations that must be cascaded to the target of the association.
Defaults to no operations being cascaded.
javax.persistence.FetchType fetch()
(Optional) Whether the association should be lazily loaded or must be eagerly fetched. The {@link FetchType#EAGER EAGER} strategy is a requirement on the persistenceprovider runtime that the associatedentities must be eagerly fetched. The {@link FetchType#LAZY LAZY} strategy is a hint to the persistence provider runtime.
java.lang.String mappedBy()
The field that owns the relationship. Required unless the relationship is unidirectional.
java.lang.Class targetEntity()
(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.