如何對查詢中進入m2m通信的背景進行檢查？

Question

有型號：

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) 

用戶與網站上的形式引入了一個月。 我提出一個要求：

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???? 
) 

如何檢查查詢用戶輸入的日期是（目前）在M2M通信天在模型中月？

Answer 1

您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之間的關係做a reverse lookup：

要引用「反向」的關係，只是使用的小寫名稱模型。

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

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