java - 如何解决Hibernate中的级联删除问题？

Question

我有三个实体。第一个是公司实体(见下文)。

@Entity
public class Company {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column
    private String name;

    @JoinColumn(name = "company_id")
    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    private List<Employee> employees;

    @OneToMany(mappedBy = "company")
    private List<HistoryRecord> historyRecords;

第二个是员工

@Entity
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    Integer id;

    @Column
    String name;

    @ManyToOne
    @JoinColumn(name = "company_id", nullable = true)
    private Company company;

    @OneToMany(mappedBy = "employee")
    private List<HistoryRecord> historyRecords;

这是我的 HistoryRecord 类

@Entity
public class HistoryRecord {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    Integer id;

    @ManyToOne
    @JoinColumn(name = "company_id")
    Employee employee;

    @ManyToOne
    @JoinColumn(name = "employee_id")
    Company company;

    @Column(name = "hire_date")
    Date hireDate;

    @Column(name = "resign_date")
    Date resignDate;

当我尝试对员工执行删除操作时，出现此错误

HTTP Status 500 - Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: Could not execute JDBC batch update; SQL [delete from employee where id=?]; constraint ["CONSTRAINT_12: PUBLIC.HISTORY_RECORD FOREIGN KEY(EMPLOYEE_ID) REFERENCES PUBLIC.EMPLOYEE(ID) 

我认为问题出在级联操作中，但我不确定。有人可以告诉我如何修复它吗？

Answer 1

问题是由于 Employee -- HistoryRecord 的关系引起的。 HistoryRecord 上的员工属性不可为空。如果您希望在删除员工时删除 HistoryRecord，则需要为 Employee 上的 HistoryRecords 添加级联属性 @OneToMany(mappedBy = "employee")。

@OneToMany(mappedBy = "employee",cascade = CascadeType.REMOVE)