hibernate之OneToOne

这里使用学生和学生的详细信息表来表述，OneToOne有三种配置

1、主键关联

     主键关联是最复杂也是最常用的关联方式。

     配置如下：studentInfo主键生成策略，使用当前对象中student属性的主键来作为本对象的主键

	@Id
	@GeneratedValue(generator="pkGenerator")
	@GenericGenerator(name = "pkGenerator", strategy = "foreign", parameters = @Parameter(name = "property", value = "student"))
	private Integer id;

 

     //optional 关联属性可以为空 接连关系由StudentInfo的属性student维持

	@OneToOne(mappedBy="student",cascade=CascadeType.ALL,optional=true)
	//@Cascade(value={org.hibernate.annotations.CascadeType.ALL})
	private StudentInfo studentInfo ;


        //optional 关联属性不能为空
	@OneToOne(cascade={CascadeType.PERSIST,CascadeType.MERGE},optional=false)
	@PrimaryKeyJoinColumn
	private Student student;

 测试代码：

 

        @Test
	public void addStudent() {
		Student student = new Student("zyn", 22,20072724L);
		StudentInfo info = new StudentInfo("3444444","成都市");
		info.setStudent(student);
		this.studentInfoDao.save(info);
	}

 

 

2、外键关联，只需要修改StudentInfo中的student属性

     通过外键student_id关联

@OneToOne(cascade={CascadeType.PERSIST,CascadeType.MERGE},optional=false)
	//@PrimaryKeyJoinColumn
	
	@JoinColumn(name="student_id",nullable=false,unique=true)
	private Student student;

 

3、中间表关联

通过中间表student_and_info关联

@OneToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE }, optional = false)
	@JoinTable(name="student_and_info",joinColumns = @JoinColumn(name = "info_id"), inverseJoinColumns = @JoinColumn(name = "student_id"))
	private Student student;