ManyToMany关系删除所有实体

Question

我有两个实体，用户和电影。他们是很多双向的关系。我的问题是，当我通过我的控制器删除一部电影时，它也会删除所有与该电影相关的实体。My user和this user角色和movie实体。我要做什么，从表中删除电影实体，并保持用户与他的角色，而不是删除他们所有。

@Data
@ToString
@EqualsAndHashCode
@Entity
@Table(name = "movies")
public class Movie {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @Column(name = "title")
    private String title;
    @Column(name = "description")
    private String description;
    @Column(name = "release_date")
    @Temporal(TemporalType.DATE)
    private Date release_date;
    @Column(name = "country")
    private String country;
    @Column(name = "category")
    private String category;
    @ManyToMany(mappedBy = "movies")
    @ToString.Exclude
    @EqualsAndHashCode.Exclude
    private Set<User> users = new HashSet<>();

@Data
@ToString
@Entity
@Table(name = "users")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @Column(name = "username")
    private String username;
    @Column(name = "password")
    private String password;
    @Transient
    private String confirmPassword;
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "users_roles", joinColumns = {@JoinColumn(name = "user_id", referencedColumnName = "id")},
            inverseJoinColumns = {@JoinColumn(name = "role_id", referencedColumnName = "id")})
    @ToString.Exclude
    @EqualsAndHashCode.Exclude
    private Set<Role> roles = new HashSet<>();

    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "users_movies", joinColumns = {@JoinColumn(name = "user_id", referencedColumnName = "id")},
            inverseJoinColumns = {@JoinColumn(name = "movie_id", referencedColumnName = "id")})
    @ToString.Exclude
    @EqualsAndHashCode.Exclude
    private Set<Movie> movies = new HashSet<>();

Answer 1

这是使用CascadeType.all时的预期行为，它隐式地包括CascadeType.Remove-在删除拥有实体时删除所有相关实体。

由于您在关联的两边都使用了cascadetype.all，因此您删除的记录超过了您实际想要的。

要避免这种情况：

• 您需要删除CascadeType.All或将其更改为适当的内容，如Merge/Persist
• 自行处理实体的删除。
• 请考虑使用批删除选项指定关联的实体ID。