pip freeze > requirements.txt #生成requirements.txt文件
pip install -r requirements.txt #安装requirements.txt文件中的包
双下划线查询
__exact #精确等于 like ‘aaa’
__iexact #精确等于 忽略大小写 ilike ‘aaa’
__contains #包含 like ‘%aaa%’
__icontains #包含 忽略大小写 ilike ‘%aaa%’，但是对于sqlite来说，contains的作用效果等同于icontains。
__gt #大于
__gte #大于等于
__lt #小于
__lte #小于等于
__in #存在于一个list范围内
__startswith #以…开头
__istartswith #以…开头 忽略大小写
__endswith #以…结尾
__iendswith #以…结尾，忽略大小写
__range #在…范围内
__year #日期字段的年份
__month #日期字段的月份
__day #日期字段的日
__isnull=True/False
关联其它App的表时报错：
SystemCheckError: System check identified some issues:
ERRORS:
stationery.Stand.userinfos: (fields.E300) Field defines a relation with model 'Userinfo', which is either not installed, or is abstract.
stationery.Stand.userinfos: (fields.E307) The field stationery.Stand.userinfos was declared with a lazy reference to 'stationery.userinfo', but app 'stationery' doesn't provide model 'userinfo'.
stationery.Stand_userinfos.userinfo: (fields.E307) The field stationery.Stand_userinfos.userinfo was declared with a lazy reference to 'stationery.userinfo', but app 'stationery' doesn't provide model 'userinfo'.
from car.models import Userinfo #错误关联方式 userinfos=models.ManyToManyField(to='Userinfo') #正确关联方式 userinfos=models.ManyToManyField(to=Userinfo)
参考链接：
http://www.cnblogs.com/yuanchenqi/articles/7690561.html #web框架，http协议介绍
http://www.cnblogs.com/yuanchenqi/category/1050267.html #django框架相关
https://www.cnblogs.com/sss4/p/7070942.html #django_ORM操作
https://code.ziqiangxuetang.com/django/django-tutorial.html #django教程
http://www.liujiangblog.com/course/django/2 #django教程
http://www.cnblogs.com/chenxuming/p/9410709.html#_label0_1 #ORM字段和字段参数
https://yiyibooks.cn/xx/Django_1.11.6/index.html #django1.11.6中文文档
https://www.django.cn/course/course-2.html
https://www.cnblogs.com/xiaoyuanqujing
http://www.cnblogs.com/linhaifeng/articles/6113086.html
http://www.cnblogs.com/alex3714/articles/5765046.html