如何对查询中进入m2m通信的条目进行背景调查？

Question

有几种型号：

class MyObject (models.Model):
     name = models.CharField ()


class Day (models.Model):
     day = models.IntegerField ()


class Month (models.Model):
     month = models.IntegerField ()
     myobj = models.ForeignKey (MyObject)
     days = models.ManyToManyField (Day)

在网站上使用表单的用户介绍一个月。我提出一个请求：

MyObject.objects.filter (month__month = <month, which is entered by the user with the form>
                                   <day, which is entered by the user with the form> in month__days????
)

如何查询用户输入的日期在模型月的m2m通信天数中是否存在？

Answer 1

You can query M2M Fields just like you would FK relationships：

day = Day.objects.get(day=1)
Month.objects.filter(days=day)

但是你需要在MyObject和Day的关系上做a reverse lookup

要引用“反向”关系，只需使用模型的小写名称即可。

day = Day.objects.get(day=5)
month = Month.objects.get(month=3)

MyObject.objects.filter(month__month=month, month__days=day)