在外键约束中获取重复的ID问题

Question

我有一个测验应用程序，具有类别，问题和答案作为实体。一类可以有多个问题，而一个问题可以有多个答案。这是我的课程，

Category.java

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

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long catId;

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

Question.java

@Entity
@Table(name = "question")
public class Question {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long questionId;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "catId", nullable = false, updatable = false)
    @JsonBackReference
    private Category category;

Answer.java

@Entity
@Table(name = "answers")
public class Answer {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long answerId;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "questionId", nullable = false, updatable = false)
    @JsonBackReference
    private Question question;

所以我创建了一个类别，可以在其中插入几个问题，但是当它回答时会说

"Duplicate entry '3' for key 'UK_a8hukb7yjph7wnrlnn8x0fcja'"

我看不到上述两种情况之间的任何关系差异，请提供帮助。