一到复合主键jpa之间的映射

Question

我确实有一个用例，两个表具有复合主键，一个表与数据库中的另一个表有关系，如何在程序级别获得这种关系，如何声明 bean 类

//表Project的复合主键

    @Embeddable
    @Data
    public class ProjectId implements Serializable {

        private static final long serialVersionUID = 12233365L;

        @Column(name = "PROJECT_CODE")
        private Integer pCode;

        @Column(name = "BOL")
        private String bol;

        @Column(name = "BOLS")
        private String bols;

        @Column(name = "EID")
        private Integer eId;

    }

//项目类

public class Project implements Serializable {

    private static final long serialVersionUID = 748569L;

    @EmbeddedId
    private ProjectId projectId;

    @Column(name = "UPDATED_DATE")
    private Date updatedDate;

    @Column(name = "CREATED_DATE")
    private Date createdDate;

}

//pcode、bol、bols、eId是复合键

// 文档表，这里有一些比较有意思的Project之间的关系p，Document是“pcode, bol, bols, eId + did”

@Embeddable
@Data
public class DocumentId implements Serializable {

    private static final long serialVersionUID = 458933256L;

    @Column(name = "PROJECT_CODE")
    private Integer pCode;

    @Column(name = "BOL")
    private String bol;

    @Column(name = "BOLS")
    private String bols;

    @Column(name = "EID")
    private Integer eId;

    @Column(name = "DID")
    private String dId;
}

//文档表

@Entity
@Table(name = "DOCUMENT")
@Data
public class Documents implements Serializable {

    private static final long serialVersionUID = 14578523695L;

    @EmbeddedId
    private DocumentId documentId;

    @Column(name = "JUR")
    private String jur;

    @Column(name = "DSEQUENCE")
    private Integer dSequence;

    @Column(name = "UPDATED_DATE")
    private Date updatedDate;

    @Column(name = "CREATED_DATE")
    private Date createdDate;

}

两个表的关系Document是Project的子表，
我想从项目方面建立一个关系。 从文档到项目也很好

如何映射表之间的一对一关系？？

Answer 1

1. 文档表应包含项目实体的关键列（pCode、bol 等）

2. 在 Document 类中添加这个成员：

   @OneToOne
   @JoinColumns({@JoinColumn(name = "pCode", referencedColumnName = "PROJECT_CODE"),
                 @JoinColumn(name = "bol", referencedColumnName = "BOL"),
                 @JoinColumn(name = "bols", referencedColumnName = "BOLS"),
                 @JoinColumn(name = "eid", referencedColumnName = "EID")})
   @MapsId("projectId")
   private Project project;
   

Answer 2

我没有足够的声望来添加评论。但是这是一个一对一的映射，因为在 Document 表中具有列 DID 证明了您可以通过具有不同的 DID 来为同一个项目拥有多个文档。我不确定我是否在这里遗漏了什么。