com.easycodebox.common.jpa

注释类型 OneToMany

@Target(value={METHOD,FIELD})
 @Retention(value=RUNTIME)
public @interface 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(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, 
            mappedBy="customer")
    public Set getOrders() { return orders; }

    In Order class:

    @ManyToOne
    @JoinColumn(name="CUST_ID", nullable=false)
    public Customer getCustomer() { return customer; }
 

从以下版本开始:

Java Persistence 1.0

可选元素概要

可选元素

限定符和类型	可选元素和说明
FetchType	fetch 此功能暂未实现
String	mappedBy The field that owns the relationship.
Class	targetEntity (Optional) The entity class that is the target of the association.

元素详细资料

targetEntity

public abstract 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.

默认值:

void.class

fetch

public abstract FetchType fetch

此功能暂未实现

默认值:

com.easycodebox.common.jpa.FetchType.LAZY

mappedBy

public abstract String mappedBy

The field that owns the relationship. Required unless the relationship is unidirectional.

默认值:

""