1,在django操作orm生成表時,會自動生成一個包含所有表名稱的表.

名字就叫:

2,實際操作.

class PricePolicy(models.Model):
    """價格與有課程效期表"""
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey(‘content_type‘, ‘object_id‘)

    valid_period_choices 
 
= ((1, ‘1天‘), (3, ‘3天‘),
                            (7, ‘1周‘), (14, ‘2周‘),
                            (30, ‘1個月‘),
                            (60, ‘2個月‘),
                            (90, ‘3個月‘),
                            (180, ‘6個月‘), (210, ‘12個月‘),
                            (540, ‘18個月‘), (720, ‘24個月
 
‘),
                            )
    valid_period = models.SmallIntegerField(choices=valid_period_choices)
    price = models.FloatField()



class Course(models.Model):
    attachment_path = models.CharField(max_length=128,     
    verbose_name="課件路徑", blank=True, null=True)
    status_choices = ((0
 
, ‘上線‘), (1, ‘下線‘), (2, ‘預上線‘))
    status = models.SmallIntegerField(choices=status_choices, 
    default=0)
    template_id = models.SmallIntegerField("前端模板id", 
    default=1)
    coupon = GenericRelation("Coupon")
    # 用於GenericForeignKey反向查詢，不會生成表字段，切勿刪除
    price_policy = GenericRelation("PricePolicy")

course_obj=models.Course.object.filter(id=1)
price_list=course_obj.price_policy.all()  #獲取與之關聯的price_policy的所有對象

for price in price_list:     #獲取所有字段,和操作其他orm一樣.
    print(price.valid_period)
    print(price.price)

上面是反向查詢,下面是正向查詢

price_obj=models.PricePolicy.objects.filter(id=1)
status=price_obj.content_type.status  
#可以直接通過content_type查詢course表中字段

django的orm--contenttype操作