Question

在JPA 2/Hibernate工作的大型和外国钥匙混杂在一起,我遇到麻烦。我试图在各国和各省建立一个简单的设想:

国家实体:

@Entity
@Table(name = "country")
public class Country extends DomainObjectBase implements Serializable {

    @Id
    @Basic(optional = false)
    @Column(name = "code")
    private String code;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "country")
    private List<Province> provinces;
}

小学关键:

@Embeddable
public class ProvincePK implements Serializable {

    @Basic(optional = false)
    @Column(name = "code")
    private String code;

    @Basic(optional = false)
    @Column(name = "country_code")
    private String countryCode;
}

省实体:

@Entity
@Table(name = "province")
public class Province extends DomainObjectBase implements Serializable {

    @EmbeddedId
    protected ProvincePK provincePK;

    @MapsId("country_code")
    @JoinColumn(name = "country_code", referencedColumnName = "code", insertable = false, updatable = false)
    @ManyToOne(optional = false)
    private Country country;
}

这为我设立了正确的表格,但有一个例外:

国家表:

code PK
...

各省

code PK FK - This is where the problem is its creating a foreign key reference to the country table s code column
country_code FK This is the only foreign key reference I want
...

我如何描绘我的实体/组合关键人物,以便产生我想要的图象? 现在,我可以把任何数据输入该省,因为我国期望该省包含《省法典》。

Thanks for any help.

Answer 1

引证。我发现,当我采用类似数据模型时,我会为我工作。

@Entity
@Table(name = "province")
@IdClass(ProvincePK.class)
public class Province extends DomainObjectBase implements Serializable {
        
    @Id
    @Basic(optional = false)
    @Column(name = "code")
    private String code;
    
    @Id
    @Basic(optional = false, insertable = false, updatable = false)
    @Column(name = "country_code")
    private String countryCode;
            
    @JoinColumn(name = "country_code", referencedColumnName = "code")
    @ManyToOne
    private Country country;
}

Answer 2

地图ID论点必须与<代码>中的属性名称相符。省PK 页: 1 标识应为insertable=true,updatable=true,然后运行。这里是法典——

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

    @EmbeddedId
    protected ProvincePK provincePK;

    @MapsId(value = "country_code")
    @JoinColumn(name = "country_code", referencedColumnName = "code")
    @ManyToOne(optional = false)
    private Country country;
}

@Embeddable
public class ProvincePK implements Serializable {

    @Basic(optional = false)
    @Column(name = "code")
    private String code;

    @Basic(optional = false)
    @Column(name = "country_code")
    private String country_code;
}

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

    @Id
    @Basic(optional = false)
    @Column(name = "code")
    private String code;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "country")
    private List<Province> provinces;
}

希望会有所助益。

友情链接