在Jpa中一对多映射

Question

如果我在单个实体A中与一个实体B有多个关系（多对一）（注释为一对多）？ 我是否必须为B中每次出现的A都添加注释？

例：

实体A：

@Entity
@Table(name = "patient")
@TableGenerator(name = "tab_gen_pa", initialValue = 30000, allocationSize = 1)
public class Patient implements Serializable, Comparable<Patient> {

 @ManyToOne
    @Column(name = "birth_region")
    private Region birthRegion;

    @ManyToOne
    @Column(name = "birth_province", length = 2)
    private Province birthProvince;

    @ManyToOne
    @Column(name = "birth_municipality")
    private Municipality birthMunicipality;

@Column(name = "living_region")
    @ManyToOne
    private Region livingRegion;

    @Column(name = "living_province", length = 2)
    @ManyToOne
    private Province livingProvince;

    @Column(name = "living_municipality")
    @ManyToOne
    private Municipality livingMunicipality;

实体B：区域，例如：

@Entity
@Table(name = "region")
@TableGenerator(name = "tab_gen_re", initialValue = 30, allocationSize = 1)
public class Region implements Serializable {

@OneToMany(mappedBy = "livingRegion")
    private List<Patient> patients;

我是否还要在Region中插入：

@OneToMany(mappedBy = "birthRegion")
        private List<Patient> patientsBirthRegion;

??

Answer 1

下面的一对关联映射，

@ManyToOne
@Column(name = "birth_region")
private Region birthRegion;


@OneToMany(mappedBy = "birthRegion")
private List<Patient> patientsBirthRegion;  

定义仅在patient列表与他们的birthRegion之间的bidirectional association 。 现在，如果您希望其他regions与这些区域的patients之间具有相似的关联类型，则需要在它们之间具有这种关联映射。