Question

我有一个包含以下字段的实体：

private Date dateOfBirth;
private String cityOfBirth;
private Long birthStateCodeId;
private Long birthCountryCodeId;
private Boolean isUSCitizen;
private Long citizenshipCountryCodeId;
private String address1;
private String address2;
private String addressCity;
private Long addressStateCodeId;
private Long addressCountryCodeId;
private String postalCode;

从上面的代码片段可以看出，我有

我使用StateCodes表中的州代码和

birthStateCodeId

addressStateCodeId

我使用CountryCodes表中的国家/地区代码的3个属性（ birthCountryCodeId，citizenshipCountryCodeId 和 addressCountryCodeId ）。

使用JPA（将Hibernate作为持久性提供程序），如何将上述5个属性（2个州代码和3个国家/地区代码）映射到两个单独的表StateCodes和CountryCodes？

Answer 1

你可以这样做：

@Entity
public class PersonIdentification {
    // primary key
    @Id // and other annotations, see JPA Spec or tutorials
    private long id;

    // regular attributes
    private Date dateOfBirth;
    private String cityOfBirth;
    private Boolean isUSCitizen;
    private String address1;
    private String address2;
    private String addressCity;
    private String postalCode;

    @ManyToOne
    private StateCode birthStateCode;
    @ManyToOne
    private StateCode addressStateCode;

    @ManyToOne
    private CountryCode birthCountryCode;
    @ManyToOne
    private CountryCode addressCountryCode;
    @ManyToOne
    private CountryCode citizenshipCountryCode;

    // setter & getter methods as needed...
}

接下来，为“代码”类型定义实体类：

@Entity
public class StateCode {
    // primary key
    @Id // and other annotations, see JPA Spec or tutorials
    private long id;

    private String code;
    private String stateName;

    // other attributes of interest

    // setter & getter methods as needed...
}

@Entity
public class CountryCode {
    // primary key
    @Id // and other annotations, see JPA Spec or tutorials
    private long id;

    private String code;
    private String countryName;

    // other attributes of interest

    // setter & getter methods as needed...
}

要减少CnP代码（与主键处理的通用方面（@Id一样），您可以check this answer。它通过引入{{1}为您提供有关如何更有效地处理此类案例的详细提示通过AbstractEntity注释。

希望有所帮助

如何通过JPA注释将不同的国家/州代码映射到基础实体？

1 个答案: