Django測驗密鑰關聯

我是 Django 和單元測驗的新手。

我正在為我的應用程式撰寫測驗，這是一個由幾個實驗室組成的學習平臺，其中包括課程和問題（3 種不同型別），問題和實驗室之間的關系是通過外鍵完成的。

我正在嘗試撰寫測驗，在其中向資料庫添加實驗室和多項選擇題。

問題是測驗總是以相同的錯誤結束：

DETAIL: Key (lab_id)=(1) is not present in table "labs_lab".

我理解這句話的意思，但是如果我提供問題的 id 以將它們鏈接到相應的測驗實驗室，怎么會發生這種情況？

謝謝

模型.py

class Lab(models.Model):
    lab_name = models.CharField(max_length=200)
    category = models.ForeignKey(Category, unique=True, null=True, on_delete=models.PROTECT)
    pub_date = models.DateTimeField('date published')
    lab_theory = models.TextField()
    def __str__(self):
        return self.lab_name

class QuestionMultipleChoice(models.Model):
    lab = models.ForeignKey(Lab, on_delete=models.CASCADE)
    type = QuestionType.multiplechoice
    question = models.CharField(max_length=200,null=True)
    option1 = models.CharField(max_length=200,null=True)
    option2 = models.CharField(max_length=200,null=True)
    option3 = models.CharField(max_length=200,null=True)
    option4 = models.CharField(max_length=200,null=True)
    answer = models.IntegerField(max_length=200,null=True)
    
    def __str__(self):
        return self.question

    @property
    def html_name(self):
        return "q_mc_{}".format(self.pk)

    @property
    def correct_answer(self):
        correct_answer_number = int(self.answer)
        correct_answer = getattr(self, "option{}".format(correct_answer_number))
        return correct_answer

    def check_answer(self, given):
        return self.correct_answer == given

測驗檔案

class TestData(TestCase):
    @classmethod
    def setUpTestData(cls):
        past_date = date(1997, 3, 2)
        future_date = date(2050, 3, 2)
        Lab.objects.create(lab_name="testlab", pub_date=datetime.now(), lab_theory="test theory")
        Lab.objects.create(lab_name="test lab past question", pub_date=past_date, lab_theory="test lab past question")
        Lab.objects.create(lab_name="test lab future question", pub_date=future_date, lab_theory="test lab future question")
        

class QuestionIndexViewTests(TestCase):
    def test_no_questions(self):
        """
        If no questions exist, an appropriate message is displayed.
        """
        response = self.client.get(reverse('labs:index'))
        self.assertEqual(response.status_code, 200)
        self.assertContains(response, "No labs are available.")
        self.assertQuerysetEqual(response.context['latest_question_list'], [])

    def test_past_question(self):
        """
        Questions with a pub_date in the past are displayed on the
        index page.
        """
        past_question = QuestionMultipleChoice.objects.create(question='This is a test question', option1='1', option2='2', option3='3', option4='4', answer='1', lab_id=2)
        response = self.client.get(reverse('labs:index'))
        self.assertQuerysetEqual(
            response.context['latest_question_list'],
            [past_question],
        )

更新：

更新：我改變了測驗，我給了“QuestionMultipleChoice”不同的引數：

question1 = QuestionMultipleChoice.objects.create(lab=1, question='This is a test question', option1='1', option2='2', option3='3', option4='4', answer='1')        

現在的結果是：

ValueError: Cannot assign "1": "QuestionMultipleChoice.lab" must be a "Lab" instance.

uj5u.com熱心網友回復：

ValueError：無法分配“1”：“QuestionMultipleChoice.lab”必須是“Lab”實體。

這意味著實驗室屬性試圖獲取實驗室實體，您可以提供實驗室實體來分配實驗室實體，您必須這樣做

lab1 = Lab.objects.create(lab_name="testlab", pub_date=datetime.now(), lab_theory="test theory")

QuestionMultipleChoice.objects.create(question='This is a test question', lab=lab1)

標籤：Python 姜戈 单元测试 django 模型

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