Question

我正在尝试使用Django的过滤器和select_related过滤值。我能够获得基本项目，但我无法获得任何连接的字段。

item = Items.objects.filter(tests__company_user_id__user_id=user_id).filter(item_id=item_id).select_related("tests__company_user").values()

我的目标是将与项目相关联的用户的数据导入到项目返回中。这可能吗？

数据模型如下所示：

class Items(models.Model):
    item_id = models.CharField(primary_key=True,max_length=100)
    mailed_date = models.DateTimeField()
    received_date = models.DateTimeField()
    last_viewed = models.DateTimeField()
    dateitemsent = models.DateTimeField()
    itemsent = models.CharField(max_length=25)
    itemret = models.CharField(max_length=25)
    dateitemret = models.DateTimeField()
    status = models.CharField(max_length=25)

class Tests(models.Model):
    tests_id = models.CharField(primary_key=True, unique=True, max_length=100)
    teststypetest_id = models.ForeignKey(TestsType)
    dateitemord = models.DateTimeField()
    testdate = models.DateTimeField()
    teststypetest_id = models.ForeignKey(TestsType)
    dateitemord = models.DateTimeField()
    testdate = models.DateTimeField()
    status = models.CharField(max_length=100)
    item_id = models.ForeignKey(Kits)
    company_user_id = models.ForeignKey(CompanyUser)

class CompanyUser(models.Model):
    user_id = models.CharField(primary_key=True,max_length=100)
    username = models.CharField(max_length=254,default="empty")
        sec_question_1 = models.CharField(max_length=254)
        sec_answer_1 = models.CharField(max_length=254)
        sec_question_2 = models.CharField(max_length=254)
        sec_answer_2 = models.CharField(max_length=254)
        sec_question_3 = models.CharField(max_length=254)
        sec_answer_3 = models.CharField(max_length=254)

Answer 1

当您使用select_related()缓存已加入的对象信息但未检索时，您需要明确提取数据：

item = Items.objects.filter(tests__company_user_id__user_id=user_id).filter(item_id=item_id).select_related("tests__company_user").values("tests__company_user_id__sec_question_1", "tests__company_user_id__sec_question_2", ...)

修改

假设您只想要CompanyUser中的两个字段：sec_question_1和sec_question_2：

from django.db.models import F item = Items.objects.filter(tests__company_user_id__user_id=user_id).filter(item_id=item_id).select_related("tests__company_user").values().annotate(q1=F('tests__company_user_id__sec_question_1'), q2=F('tests__company_user_id__sec_question_2'))

获取其他表Django filter / select_related

1 个答案: