Question

CREATE TABLE `incident` (
  `author_id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(45) NOT NULL,
  `email` varchar(45) NOT NULL,
  PRIMARY KEY (`author_id`)
);

CREATE TABLE `adr` (
  `author_id` int(11) NOT NULL,
  `title` varchar(128) NOT NULL,
  `description` varchar(512) NOT NULL,
  `published` date NOT NULL, 
  PRIMARY KEY (`author_id`),
  KEY `author_fk` (`author_id`),
  CONSTRAINT `author_fk` FOREIGN KEY (`author_id`) REFERENCES `incident` (`author_id`)
);

这是事件和adr之间的一对一映射。在adr表中，author_id是PK＆amp; FK。

我们如何为这对一对一关系之王创建一个实体类。

尝试过的解决方案

//事件表实体类

 Entity
    @Table(name="INCIDENT")
    public class Incident implements Serializable {
        private static final long serialVersionUID = 1L;

        @Id
        @SequenceGenerator(name="IR_TB_INCIDENT_HDR_INCIDENTID_GENERATOR", sequenceName="IR_SEQ_INCIDENT_ID")
        @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="IR_TB_INCIDENT_HDR_INCIDENTID_GENERATOR")
        @Column(name="AUTHOR_ID")
        private int authorId;

        @Column(name="NAME")
        private String name;

        @Column(name="EMAIL")
        private String email;

@OneToOne(cascade = {CascadeType.PERSIST,CascadeType.MERGE, CascadeType.REMOVE}, fetch = FetchType.LAZY,  mappedBy="Incident")
    private Adr  adr;
        /** constructors , getters & sertters **/
        }




    compile time Exception in Incident.java
In attribute 'adr', the "mapped by" attribute 'incident' has an invalid mapping type for this relationship.

如何定义adr实体，以便作者ID引用事件表中的作者ID 试过这个但没有工作

@Entity
@Table(name="ADR")
public class Adr implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name="INCIDENT_ID") 
    private Incident Incident;

    @Column(name="TITLE")
    private String title;

    /** rest of the fields and methos **/
    }

与场的一对一映射充当PK＆amp; amp;使用级联时FK值不保存到db

0 个答案: