链接到实体-基于子辈和孙辈排除子辈

Question

我需要帮助解决一个我想不明白的问题。我想要一份只有没有回答的问题的调查问卷。

要清楚，一个人应该能够要求一份问卷，回答一个问题，比如说，总共5个问题。然后，当一个人下次请求问卷时，它应该返回，但只有4个问题(未回答的问题)。

我试过它与lambda包括也，但不能让它工作。任何帮助都是非常感激的!

类的结构类似于

public class Questionnaire()
{
    public int Id {get; set;}
    public List<Question> {get; set;}
}
public class Question()
{
    public int Id {get; set;}
    public int QuestionnaireId {get; set;}
    public List<Answer> {get; set;}
}
public class Answer()
{
    public int Id {get; set;}
    public int QuestionId {get; set;}
    public int QuestionnaireId {get; set;}
    public List<ReceivedAnswer> {get; set;}
}
public class ReceivedAnswer()
{
    public int AnswerId {get; set;}
    public int QuestionId {get; set;}
    public int QuestionnaireId {get; set;}
    public int PersonId {get; set;}
}

Answer 1

假设您有表:

Questionnaires[QuestionnairesID, QuestionID]
ReceivedAnswers[PersonID , AnswerID]
Questions[QuestionID,Question]
Answers[AnswerID,QuestionID,Answer]

Linq查询将像:

var pp = (from q in questionnaire.Questions
         join a in question.Answers on q.questionid equals a.questionid
         join ra in ReceivedAnswers on ra.answerid equals a.answerid
         where ra.personid == inPersonID
         select q.questionid).ToList();
var output = from questionnaire in _unitOfWork.Questionnaires
        where questionnare.Id == questionnaireId && !pp.contains(q.questionid)
        select questionnaire