沒有鑑別或層次OneToOne映射

Question

我有一箇舊的數據庫中的兩個表，我試圖創建它的Java模型（使用JPA 2.0和Hibernate 4）

create table master (
    master_id      number(38) not null, --this is the primary key 
    ... 
) 

create table child (
    master_id      number(38) not null, --the primary key and also a foreign key to master.id 
    ... 
) 

我創建了實體但是我對每個類使用哪些註釋感到困惑。 @JoinColumn? @PrimaryKeyJoinColumn? @Id？

我知道Master將管理Java層的持久性。也就是說，持續更新將從Master級聯。這一定是一個基本問題，但我是JPA的新手。

@Entity 
class Master { 

    @Id 
    @Column (name="master_id") 

    @OneToOne 
    private Child child; 

} 

@Entity 
class Child { 

    @OneToOne 
    private Master master; 
} 

Answer 1

見下：

@Entity 
class Master { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private Long id; 

    @OneToOne(mappedBy = "master") 
    private Child child; 
} 

@Entity 
class Child { 

    @Id 
    @OneToOne 
    @JoinColumn(name = "master_id") 
    private Master master; 
} 

更多信息：

http://en.wikibooks.org/wiki/Java_Persistence/Identity_and_Sequencing#Primary_Keys_through_OneToOne_and_ManyToOne_Relationships