@Target(value={METHOD,FIELD}) @Retention(value=RUNTIME) public @interface OneToMany
 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;}
    
 | Modifier and Type | Optional Element and Description | 
|---|---|
| CascadeType[] | cascade(Optional) The operations that must be cascaded to 
 the target of the association. | 
| FetchType | fetch(Optional) Whether the association should be lazily loaded or
 must be eagerly fetched. | 
| String | mappedByThe field that owns the relationship. | 
| boolean | orphanRemoval(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. | 
| Class | targetEntity(Optional) The entity class that is the target
 of the association. | 
public abstract Class targetEntity
Defaults to the parameterized type of the collection when defined using generics.
public abstract CascadeType[] cascade
Defaults to no operations being cascaded.
 When the target collection is a java.util.Map, the cascade element applies to the
 map value.
public abstract FetchType fetch
public abstract String mappedBy
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