Hibernate4一对一关系映射（共享主键方式）

示例：一个人（person） 住一个地址（address），一个地址有一个人。

 

public class Person {

    private Integer id;
    private String name;

    private Address address;

    //getter and setter
}

 

public class Address {

    private Integer id;
    private String detail;

    private Person person;

    //getter and setter
}

 

用XML映射

 

<hibernate-mapping package="org.monday.hibernate4.domain">
    <class name="Person" table="tbl_person">
        <id name="id">
            <generator class="identity" />
        </id>
        <property name="name" />
        <one-to-one name="address" class="Address" />
    </class>
</hibernate-mapping>

 

<hibernate-mapping package="org.monday.hibernate4.domain">
    <class name="Address" table="tbl_address">
        <id name="id">
            <generator class="foreign">
                <param name="property">person</param>
            </generator>
        </id>
        <property name="detail" />
        <one-to-one name="person" class="Person" constrained="true" />
    </class>
</hibernate-mapping>

1、Address的主键生成策略使用foreign方式，表示通过外键与Person对象共享标识符属性。
2、<one-to-one>标签的constrained属性设置为true，表示约束Address对象的标识符属性值必须与
person属性所对应的持久化对象的标识符属性相同。

 

用@Annotation映射

 

@Entity
@Table(name = "tbl_person")
public class Person {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;

    @OneToOne
    @PrimaryKeyJoinColumn
    private Address address;

    // getter and setter
}

 

@Entity
@Table(name = "tbl_address")
public class Address {

    @Id
    @GeneratedValue(generator = "myForeignGenerator")
    @GenericGenerator(name = "myForeignGenerator",
            strategy = "foreign",
            parameters = @Parameter(name = "property", value = "person"))
    private Integer id;
    private String detail;

    @OneToOne(optional = false)
    @PrimaryKeyJoinColumn
    private Person person;

    // getter and setter
}

 

@OneToOne的optional=false表示在address这端添加一个外键约束
@PrimaryKeyJoinColumn定义了一对一关联

 

测试代码

 

Person person = new Person();
person.setName("monday");

Address address = new Address();
address.setDetail("shanghai");

person.setAddress(address);
address.setPerson(person);

session.save(person);
session.save(address);

 

 SQL schema

Hibernate:
    create table tbl_address (
        id integer not null,
        detail varchar(255),
        primary key (id)
    )
Hibernate:
    create table tbl_person (
        id integer not null auto_increment,
        name varchar(255),
        primary key (id)
    )
Hibernate:
    alter table tbl_address
        add index FKD0C46473E8935A42 (id),
        add constraint FKD0C46473E8935A42
        foreign key (id)
        references tbl_person (id)
Hibernate:
    insert
    into
        tbl_person
        (name)
    values
        (?)
Hibernate:
    insert
    into
        tbl_address
        (detail, id)
    values
        (?, ?)