java - spring boot中外键引用主键

Question

1. 我正在努力添加 MCQ 问题、选项和答案。

2. Question、Option 和Answer 三张表。

下面是我的数据库模式

1. questionId(问题表)是主键，questionId(选项表)是外键。

2. questionId(问题表)是主键，questionId(答案表)是外键。

3. optionId(选项表)是主键，optionId(答案表)是外键。

我无法链接主键和外键 - 请帮助我改进。

问题表:

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

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@JoinColumn (name = "questionId")
private Long questionId;

@Column(nullable = false)
private String question;

@OneToOne(fetch = FetchType.LAZY)
@JoinTable( name = "Answer", joinColumns = @JoinColumn ( name = "question_id"), inverseJoinColumns = @JoinColumn( name = "option_id"))
private List <Option> options;

@OneToMany(mappedBy = "questionId", cascade = CascadeType.ALL)
private Set<Option> option;

public Question() { }

public Long getMcqId() {
    return questionId;
}

public void setMcqId(Long mcqId) {
    this.questionId = mcqId;
}

public String getQuestion() {
    return question;
}

public void setQuestion(String question) {
    this.question = question;
}

@Override
public String toString() {
    return "SessionMcqModel{" +
            "mcqId=" + questionId +
            ", question='" + question + '\'' +
            '}';
}

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;
    Question question1 = (Question) o;
    return questionId.equals(question1.questionId) &&
            question.equals(question1.question) &&
            options.equals(question1.options) &&
            option.equals(question1.option);
}

@Override
public int hashCode() {
    return Objects.hash(questionId, question, options, option);
}
}

答案表:

@Entity
@Table(name = "mcq_Options")
public class Option {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "option_id")
private int optionId;

private String option;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn
private Question questionId;

public Option() { }

public Option(String option, Question questionId) {
    this.option = option;
}

public int getOptionId() {
    return optionId;
}

public void setOptionId(int optionId) {
    this.optionId = optionId;
}

public String getOption() {
    return option;
}

public void setOption(String option) {
    this.option = option;
}

public Question getQuestionId() {
    return questionId;
}

public void setQuestionId(Question questionId) {
    this.questionId = questionId;
}

@Override
public String toString() {
    return "Option{" +
            "optionId=" + optionId +
            ", option='" + option + '\'' +
            ", questionId=" + questionId +
            '}';
}
}

错误:

引起:org.hibernate.AnnotationException:com.bluepi.TrainingProject.model.Question.options 上的@OneToOne 或@ManyToOne 引用未知实体:java.util.List

Answer 1

问题出在 Question 和 Option 之间的关系上

@OneToOne(fetch = FetchType.LAZY)
@JoinTable( name = "Answer", joinColumns = @JoinColumn ( name = "question_id"), inverseJoinColumns = @JoinColumn( name = "option_id"))
private List <Option> options;

您正在尝试将列表映射到不正确的 1-1 关系，您可能想要使用的是使用 @OneToMany 注释而不是 的 1-N 关系>@OneToOne