一次在Entity中插入多个相关表

Question

我有三个表通过外键连接。 我试图在问题表中插入1行，在另外两个表中插入两行。 我收到错误'插入语句与外键约束冲突'提前感谢您的帮助

public void setMultiAnswer()
{
try
{
    string question = "Question 1"
    responsesList.Add("Answer1");
    responsesList.Add("Answer2");
    questionResponsesList.Add(false);
    questionResponsesList.Add(true);

    using (Entities testEntity = new Entities())
    {
        Question questionObj = new Question();
        questionObj.Question1 = question;
        questionObj.CreatedBy = "test";
        questionObj.CreatedDate = DateTime.Now;

        QuestionRespons questionResponsesObj = new QuestionRespons();
        // fill response
        foreach (var questionResponse in questionResponsesList)
        {
            questionResponsesObj.CorrectResponse = questionResponse;
        }

        questionObj.QuestionResponses.Add(questionResponsesObj);

        Response responseObj = new Response();

        // fill response 
        foreach (var response in responsesList)
        {
             responseObj.Response1 = response;
             responseObj.CreatedBy = "test";
             responseObj.CreatedDate = DateTime.Now;
        }
        questionResponsesObj.Response = responseObj;

        testEntity.Questions.Add(questionObj);
        testEntity.SaveChanges();
    }
}
catch (Exception ex)
{
    Console.Write(ex);
}

Answer 1

听起来你的问题id是自动生成的。 在这种情况下int questionId = questionObj.QuestionID; 只有在SaveChanges()调用后才能工作。

通常，如果您有一个带有外键的EntitySet，则更容易使用导航属性而不是自己构建id引用。

Question questionObj = new Question();
questionObj.CreatedBy = "Test";
questionObj.CreatedDate = DateTime.Now;

QuestionRespons questionResponsesObj = new QuestionRespons();
// fill question response here
questionObj.QuestionResponses.Add(questionResponseObj);

Response responseObj = new Response();
// fill your response here
questionResponsesObj.Response = reponseObj;
// if you do the above in your loop you should be fine

testEntity.Questions.Add(questionObj);
testEntity.SaveChanges();

要匹配您的示例：

public void setMultiAnswer()
{
    try
    {
        string question = "Question 1"
        responsesList.Add("Answer1");
        responsesList.Add("Answer2");
        questionResponsesList.Add(false);
        questionResponsesList.Add(true);

        using (Entities testEntity = new Entities())
        {
            Question questionObj = new Question();
            questionObj.Question1 = question;
            questionObj.CreatedBy = "Test";
            questionObj.CreatedDate = DateTime.Now;
            testEntity.Questions.Add(questionObj);

            for (int i = 0; i < responsesList.Count; i++)
            {
                // i am not sure about your relation here, but i assume you require one QuestionResponse per response
                // which is why a moved the line of code
                QuestionRespons questionResponsesObj = new QuestionRespons();
                questionObj.QuestionResponses.Add(questionResponsesObj);

                Response responseObj = new Response();
                responseObj.Response1 = responsesList.ElementAt(i);
                responseObj.CreatedBy = "Test";
                responseObj.CreatedDate = DateTime.Now;

                if (!string.IsNullOrEmpty(responseObj.Response1))
                {
                    questionResponsesObj.Response = responseObj;
                    questionResponsesObj.CorrectResponse = questionResponsesList.ElementAt(i);
                }

            }
            testEntity.SaveChanges();
        }
    }
    catch (Exception ex)
    {
        Console.Write(ex);
    }
}

Answer 2

改变顺序

int questionId = questionObj.QuestionID;
testEntity.SaveChanges();

成

testEntity.SaveChanges();
int questionId = questionObj.QuestionID;

您创建了一个新的实例questionObj ，其默认ID为0.只有在调用SaveChanges() ，才应为ID分配新分配的实际ID值。

所以，这里发生的是你用默认值0而不是真实ID记住questionId 。 作为一个结果，问题和答复之间的关系总是错误的。

Answer 3

如果我是你，我会删除这个QuestionResponse表，只保留问题和答案。 使用导航属性而不是直接设置外键。

    Question questionObj = new Question
    {
        Text = question,
        CreatedBy = "Test",
        CreatedDate = DateTime.Now
    };

    foreach(var response in responsesList.Where(x => !string.IsNullOrEmpty(x)))
    {
        Response responseObj = new Response
        {
            Text = response,
            IsCorrect = true,
            CreatedBy = "Test",
            CreatedDate = DateTime.Now
        }

        questionObj.Add(responseObj);
    }

    testEntity.Questions.Add(questionObj);
    testEntity.SaveChanges();