使用 hibernate 和 jpa 添加外鍵

Question

這些是我的課程：

@Entity
@Table(name="assessment")
public class AssesmentProperties {

  @Id
  @Column(name="AssessmentId")
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private Long AssessmentId;

  @Column(unique=true,nullable=false)
  private String AssessmentName;

  private String AssessmentLevel;
  private String  Specialization;
  private int time;
  private String keywords;
  private int NoOfSections;

  //getters and setters
}


@Embeddable
public class SettingsPrimary implements Serializable {

  private Long AssessmentId;

  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private Long Section;

 //getters and setters
}


@Entity
@Table(name="section")
public class SectionProperties {

  @EmbeddedId
  private SettingsPrimary PrimaryKey;

  private String SectionType;
  private int Weightage;
  private int time;
  private int NoOfQuestions;

  //getters and setters
}

在表section我需要將assessment_id ID 創建為assessment表的 FK 並在刪除時設置級聯。 我試圖用不同的方式來做到這一點，但沒有成功。

Answer 1

也許這可以幫助你。

@Entity
@Table(name="section")
public class SectionProperties {

  @Id
  private Long PrimaryKey;

  @ManyToOne(cascade = CascadeType.ALL)
  @JoinColumn(name = "assessment_id", referencedColumnName="AssessmentId")
  private AssesmentProperties AssesmentProperties;

  private String SectionType;
  private int Weightage;
  private int time;
  private int NoOfQuestions;

  //getters and setters
}

我將 SectionProperties id 更改為Long並將 AssessmentProprties 映射到 ManytoOne 道具。 這樣，綁定到 Section 的 AssessmentProperties 總是會被刪除，關聯的 SectionProperties 也會被刪除。