java - 在hibernate中使用主键和外键组合映射三个表

Question

我必须在 hibernate 中映射这些表，事实已经尝试了很多方法，但对我来说没有用，如果我可以帮助解决这个问题，我不会粘贴我的代码，因为我认为它不正确，我变化很大。

餐 table 国家

idCountry(PK)

国家名称

表区域

idRegion(PK)

idCountry(PK、FK)

区域名称

表省份

idProvinces (PK)

idRegion(PK、FK)

省份名称

希望您能帮助我，非常感谢

Answer 1

这是表映射:

@Entity
@Table(name = "COUNTRY")
public class Country implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "idCountry", unique = true, nullable = false)
    private int countryId;

    @Column(name = "countryName", nullable = false)
    private String countryName;

    @OneToMany(mappedBy = "regionPk.country", cascade = CascadeType.ALL)
    private Set<Region> regions = new HashSet<Region>(0);

    // Generate Getters, Setters, hashCode() and equals()

}

@Entity
@Table(name = "REGION")
public class Region implements Serializable {

    @EmbeddedId
    private RegionPk regionPk;  //  RegionPk contains the composite PK

    @Column(name = "RegionName", nullable = false)
    private String regionName;

    @OneToMany(mappedBy = "provincePk.region", cascade = CascadeType.ALL)
    private Set<Province> provinces = new HashSet<Province>(0);

    // Generate Getters, Setters, hashCode() and equals()

}

@Embeddable
public class RegionPk implements Serializable {

    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "idRegion", unique = true, nullable = false)
    private int regionId;

    @ManyToOne
    @JoinColumn(name = "idCountry", nullable = false)
    private Country country;

    // Generate Getters, Setters, hashCode() and equals()

}

@Entity
@Table(name = "PROVINCES")
public class Province implements Serializable {

    @EmbeddedId
    private ProvincePk provincePk;  //  ProvincePk contains the composite PK

    @Column(name = "ProvinceName", nullable = false)
    private String provinceName;

    // Generate Getters, Setters, hashCode() and equals()

}

@Embeddable
public class ProvincePk implements Serializable {

    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "idProvinces", unique = true, nullable = false)
    private int provinceId;

    @ManyToOne
    @JoinColumn(name = "idRegion", nullable = false)
    private Region region;

    // Generate Getters, Setters, hashCode() and equals()

}