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Spring JPA使用其他表引用表

jpa hibernate spring java

StuartDTO · 技术社区 · 5 年前

这是我的问题课

@Entity(name = "question")
public class Question extends DateAudit {
    @Id
    @Column(name = "question_id")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "question_seq")
    @SequenceGenerator(name = "question_seq", allocationSize = 1)
    private Long id;

    @Column(name = "name")
    @NotBlank(message = "Question name can not be blank")
    private String name;

    @Column(name = "is_exam_question", nullable = false)
    private Boolean is_exam_question;

    @ManyToOne(fetch = FetchType.EAGER, cascade = { CascadeType.PERSIST, CascadeType.MERGE })
    private Set<Answer> answers = new HashSet<>();

}

这里我遗漏了一些东西,因为我想知道哪个用户回答了这个问题,以及他成功与否的次数。

我的答案是

@Entity(name = "answer")
public class Answer {

    @Id
    @Column(name = "answer_id")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "answer_seq")
    @SequenceGenerator(name = "answer_seq", allocationSize = 1)
    private Long id;

    @Column(name = "answer_to_question")
    @NotBlank(message = "Answer to question name can not be blank")
    private String answer_to_question;

    @ManyToOne
    private Question question;
}

解释得更好

如何为问题添加多个答案以及如何将此答案分配给问题?

0 回复 | 直到 5 年前

Muhammad Waqas 5 年前

创建新类名为测验班

@Entity
public class Quiz{

@Id
private int id;

private String quizName;

private String quizDescription;

private int passingScore;

private int totalScore;

// Getter and setters
}

问题.类会像这样

@Entity(name = "question")
public class Question extends DateAudit {
    @Id
    @Column(name = "question_id")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "question_seq")
    @SequenceGenerator(name = "question_seq", allocationSize = 1)
    private Long id;

    @Column(name = "name")
    @NotBlank(message = "Question name can not be blank")
    private String name;

    @Column(name = "is_exam_question", nullable = false)
    private Boolean is_exam_question;

    @OneToMany(fetch = FetchType.EAGER, cascade = { CascadeType.PERSIST, CascadeType.MERGE },mappedBy="question")
    private Set<Answer> answers = new HashSet<>();

    @ManyToOne
    private Quiz quiz;

}

@Entity
public class Tests{

private int id;

@ManyToOne
private Quiz quiz;

@ManyToOne
private User user;

private int score;

private String status; // failed or passed

}

我想这对你有帮助。请随意问我更多的问题。