Question

我有2个表的问题和问题选项。问题具有复合键。当我通过ID查询问题时，如何获得问题选项。如何确保我也能获得问题选项。到目前为止，我只得到问题。我应该更改映射还是应该添加一些属性

问题

@Entity
@Getter
@Setter
@JsonIgnoreProperties({"assessment"})
public class Question implements Serializable {

    @EmbeddedId
    private QuestionAssessmentKey questionAssessmentKey;

    public QuestionAssessmentKey getQuestionAssessmentKey() {
        return questionAssessmentKey;
    }

    public void setQuestionAssessmentKey(QuestionAssessmentKey questionAssessmentKey) {
        this.questionAssessmentKey = questionAssessmentKey;
    }

    @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name =  "assessmentId", insertable = false, updatable = false)
    private Assessment assessment;

    private String questionText;

    private String questionURL;

    private QuestionStatus questionStatus;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumns({
            @JoinColumn(name="assessmentId", referencedColumnName = "assessmentId"),
            @JoinColumn(name="questionNumber", referencedColumnName = "questionNumber")
    })
    private List<QuestionOption> questionOptions;

    public List<QuestionOption> getQuestionOptions() {
        return questionOptions;
    }

    public void setQuestionOptions(List<QuestionOption> questionOptions) {
        this.questionOptions = questionOptions;
    }

    public Assessment getAssessment() {
        return assessment;
    }

    public void setAssessment(Assessment assessment) {
        this.assessment = assessment;
    }
    //    private int questionNumber;
    private QuestionTypes questionType;
//Getters and setters
}

QuestionOptions

@Entity
public class QuestionOption {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int questionOptionId;

    @ManyToOne
    @JoinColumns({
            @JoinColumn(name="assessmentId", referencedColumnName = "assessmentId"),
            @JoinColumn(name="questionNumber", referencedColumnName = "questionNumber")
    })
    private Question question;

    private Character questionOption;

//Getter and setter
}

QuestionAssessmentKey

@Embeddable
public class QuestionAssessmentKey implements Serializable {

    private int questionNumber;

    private String assessmentId;
}

Answer 1

同样，您无法在单个查询中获取所有数据，因为它是问题和问题选项之间的一对多关系。但是，当您在获取的getQuestionOptions实体上调用Question时，它应该加载并返回相应的选项集。

在JPA中查询父表时如何从子表中获取字段

1 个答案: