Is JPA 2 a foreign key that includes only one field from a composite primary key?

Question

I'm having trouble getting the composite primary key and foreign keys working in JPA 2 / Hibernate. I am trying to create a simple scenario with countries and provinces:

Country:

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

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

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

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

Primary Key of the Province:

@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;
}

Provinces:

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

    @EmbeddedId
    protected ProvincePK provincePK;

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

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

This creates the right tables for me with one exception:

Country table:

• PK code
• name

Table of provinces

• code PK FK - the problem here is that it creates a foreign key link for the code column of the country table.
• country_code FK This is the only foreign key link I want
• name

/ , ? - , , !

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Answer 1

. , , .

@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;


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

    @JoinColumn(name = "country_code", referencedColumnName = "code")
    @ManyToOne
    private Country country;

}

Answer 2

@MapsID ProvincePK. @JoinColumn insertable=true,updatable=true, . -

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

@EmbeddedId
protected ProvincePK provincePK;

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

@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;

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

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

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