java - Hibernate 注解映射、JPA 孤儿删除

Question

我试图建立类别和出版物类(OneToMany)之间的关系，并且我需要删除属于特定类别的所有出版物。 我不知道是否缺少一些注释，但这是我执行查询时的错误:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute update query org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:973) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852) javax.servlet.http.HttpServlet.service(HttpServlet.java:618) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837) javax.servlet.http.HttpServlet.service(HttpServlet.java:725) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

org.hibernate.exception.ConstraintViolationException: could not execute update query.

org.postgresql.util.PSQLException: ERROR: update or delete on table "category" violates foreign key constraint "fkf5bea17d42c4af41" on table "publication" Detail: Key (id)=(190) is still referenced from table "publication".

我的源代码如下:

类别类别:

@Entity
@Table(name = "category")
public class Category {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;
    private String name;
    private String description;

    @OneToMany(mappedBy="category", orphanRemoval=true)
    private List<Publication> publications;

    // Getters and Setters
}

出版类别:

@Entity
@Table(name = "Publication")
public class Publication {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;
    private String title;
    private String content;

    @ManyToOne
    @JoinColumn(name = "id_category")
    private Category category;

    // Getters and Setters
}

删除类别的查询:

@Override
public void deleteCategory(int id) {
    sessionFactory.getCurrentSession()
     .createQuery("DELETE FROM Category WHERE id="+id).executeUpdate();
}

提前感谢大家。

Answer 1

您需要将删除操作级联到发布:

@OneToMany(mappedBy="category", orphanRemoval=true, cascade = CascadeType.ALL)
private List<Publication> publications;

<小时/>

编辑:

由于添加级联并不能解决您的问题，并且您正在使用 Hibernate，因此添加特定于 Hibernate 的级联注释可能会有所帮助。在这种情况下，您不需要上面的 JPA 参数:

@OneToMany(mappedBy="category", orphanRemoval=true)
@org.hibernate.annotations.Cascade(org.hibernate.annotations.CascadeType.ALL)
private List<Publication> publications;

这破坏了到不同对象关系映射框架的可移植性，因为它不再是纯粹的 JPA - 但它在过去的某些情况下对我有帮助。