第四十四章 Django ORM

1. 路由系统
  def test():
   pass
  url(r'^test$', test)

  创建app：
   python3 mange.py startapp app名称

   from app01 import views
   url(r'^test$', views.test)

  反向路由：
   urls:
    url(r'^test1$', views.test, name='xxx')
   html:
    <form action="{% url ’xxx‘ %}">
    </form>
  路由分组：
   include
  urls.py:
   url(r'^test/(\w+)/(\w+)/')
  views.py:
   def test(request, id, name):


  urls.py:
   url(r'^test/(?P<id>\w+)/(?P<name>\w+)/')
  views.py:
   def test(request, name,id):


  建议大家使用：
   创建一个app，然后在app的views.py中写自己的业务逻辑函数， urls.py 路由匹配，只是进行分发


  CBV和FBV：
   FBV：之前所有的都是基于FBV（写函数）

   CBV:

    urls.py:
     url('^login', views.Login.as_view())

    views.py:

     from django.views import View
     class Login(View):

      def get():
       pass

      def post():
       pass

     http协议支持的方法：get、post、put（更新）、delete(删除)、patch(部分更新)

     form支持get、post
     ajax 支持大多数方法


2. ORM配置和

   a. 自己创建数据库

   b. settings:

    default: mysql配置链接

    install_app: app01

   c. __init__.py:
    import pymysql
    pymysql.install_as_mysqldb

   d.在models.py:

    class UserType(models.Model):
     title= models.Charfiled(max_legnt=32)

    class Userinfo(models.MOdel):

     ### id不用写，自动生成
     name = models.Charfiled(max_legnt=32)
     ut = models.ForeignKey('UserType') ### ut_id


   e.python3 mange.py makemigrations ## 生成migrations文件
     python3 mange.py migrate   ### 根据生成的migrations文件生成表


3. 基本使用

   增

    models.Userinfo.objects.create(name='xxxx')


   查
    单表查询：
     ### 查询所有
     res = models.userinfo.objects.all()
     res### query set [ obj, obj, obj,....]

     ### 查询一个
     res =   models.userinfo.objects.first()
     res ### obj


     ### 过滤
     res = models。userinfo.objects.filter(id=1)
     res = models。userinfo.objects.filter(id__lt=1)
     res = models。userinfo.objects.filter(id__lte=1)
     res = models。userinfo.objects.filter(id__gte=1)
     res = models。userinfo.objects.filter(id__gt=1)

     ### 查询某一列的值
     res = models。userinfo。objects.values('name').all()
     res ### query set[ {"name":'zekai'}, ....]

     res = models.userinfo.objects.value_list('name').all()
     res ### query set[(name),(), ]

    一对多：

     ### 查询所有
     res = models.userinfo.objects.all()
     res### query set [ obj, obj, obj,....]

     ### 查询一个：
     res =   models.userinfo.objects.first()


      ### 正向查询
     # res = models.UserInfo.objects.filter(name='zekai').all()
     # res = models.UserInfo.objects.all()
     # print(res) ### <QuerySet [<UserInfo: UserInfo object>]>
     # for obj in res:
     #     print(obj.id, obj.name, obj.ut.title)

### 反向查询
### 需求：查询usertype下所有类型的包含的人

     # res = models.UserType.objects.all()
     # print(res)### <QuerySet [<UserType: UserType object>, <UserType: UserType object>, <UserType: UserType object>]>
     # ### 外键关联的表名小写_set.filter()
     # for obj in res:
     #     print(
     #         obj.id, ## id = 1
     #         obj.title, ### 保安部
     #         obj.userinfo_set.all() #### models.UserInfo.objects.filter(ut_id=1).all()
     #     )

     ### 神奇的双下画线
     ## 跨表查询
     res = models.UserInfo.objects.values('name', "ut__title")
     print(res)


   删
    .delete()

   改
    .filter().update()

今日内容：

1. ORM

  a.基本查
   all()
   values()
   value_list()


  b.高级查询
   ## 1. in
   # res = models.UserInfo.objects.filter(id__in=[1,2,3])
   # print(res)

   ## 2. not in
   # res = models.UserInfo.objects.exclude(id__in=[1,2,3])
   # print(res)

   ## 3. like
   ## where name like 'ze%' ## 以ze开头的所有的数据
   ### startswith：以某单词开头
   ### istartswith : ignore (忽略) 以某单词开头忽略大小写
   # res = models.UserInfo.objects.filter(name__startswith="ze")
   # res = models.UserInfo.objects.filter(name__istartswith="ze")
   # print(res)

   ## where name like '%ze'
   ## endswith : 以某个单词结尾
   ## iendswith: ignore (忽略) 以某单词结尾忽略大小写
   # res = models.UserInfo.objects.filter(name__endswith='ze')

   ## where name like "%ze%"
   ### contains : 包含某一个单词
   ### icontains: 包含某一个单词不区分大小写
   # models.UserInfo.objects.filter(name__contains='ze')

### 4. between.. and..
### models.UserInfo.objects.filter(id__range=[1,2])

   ### 5. limit 10, 20
   # models.UserInfo.objects.all()[开始位置:结束位置]
   # models.UserInfo.objects.all()[0:10]
   # models.UserInfo.objects.all()[10:20]

   ### 6. order by age asc, name desc
   # res = models.UserInfo.objects.all().order_by('id') ## 默认升序
   ### 前面加一个 ‘-’ 代表降序
   # res = models.UserInfo.objects.all().order_by('-id','name')
   # print(res.query)

   ### 7. group by
   # from django.db.models import Count, Max, Min, Sum
   # res = models.UserInfo.objects.values('name').annotate(xxx=Count('id'))
   # print(res.query)

   # SELECT "app01_userinfo"."id", COUNT("app01_userinfo"."name") AS "xxx"
   # FROM "app01_userinfo"
   # GROUP BY "app01_userinfo"."id";

   #### 8. only: 只取某一个列的值
   ## SELECT "app01_userinfo"."id", "app01_userinfo"."name", "app01_userinfo"."age" FROM "app01_userinfo"
   # res = models.UserInfo.objects.only('name', 'age').all()
   # print(res) ## <QuerySet [<UserInfo: UserInfo object>, <UserInfo: UserInfo object>, <UserInfo: UserInfo object>, <UserInfo: UserInfo object>, <UserInfo: UserInfo object>, <UserInfo: UserInfo object>]>

   ### 9. defer: 除了这几列之外的所有列的值
   ### SELECT "app01_userinfo"."id", "app01_userinfo"."ut_id" FROM "app01_userinfo"
   # res = models.UserInfo.objects.defer('id','name', 'age').all()
   # print(res.query)

   ### 10.using: 想要使用哪个数据库，就将这个数据库的配置名称写到using中
   # models.UserInfo.objects.all().using("xxxx")


   ### 11. 表中总共多少条数据
   # res = models.UserInfo.objects.count()
   # print(res)

   ### 12. 第一条数据
   # res = models.UserInfo.objects.first()
   # print(res)

## 13.最后一条数据
# res = models.UserInfo.objects.last()

   ## 14.gt lt
   # res = models.UserInfo.objects.filter(id__gt=3)
   # res = models.UserInfo.objects.filter(id__gte=3)
   # res = models.UserInfo.objects.filter(id__lt=3)
   # res = models.UserInfo.objects.filter(id__lte=3)

   ### 15. and操作
   # res = models.UserInfo.objects.filter(id=1, name='zekai')
   # print(res.query)

   ### 16.or操作
   # from django.db.models import Q
   # res = models.UserInfo.objects.filter( Q(Q(id=1) | Q(name='zekai')) & Q(name='xxxx') )
   # print(res.query)

   ### 17. 在原来的基础上更新值
   # from django.db.models import F
   # models.UserInfo.objects.update(age = F('age') + 1)

   ## 18。原生sql
   # from django.db import connection
   # cursor = connection.cursor()
   # cursor.execute("select * from app01_userinfo where id=%s", [1,])
   # # res = cursor.fetchall()
   # # res = cursor.fetchone()
   # # print(res)

   ## 19. 原生sql
   # models.UserInfo.objects.raw('select * from app01_userinfo')



   注意：
    1. orm能实现的功能，尽量使用orm实现
    2. 不建议大家以后再自己的业务逻辑中，混着用


  c. 一对多关系操作：
   正向查询和反向查询
   __ 神奇的双下画线跨表查询


  d. 多对多关系：

    自己写：
     models.py:
      class Boy(models.Model):
       name = models.CharField(max_length=32, null=True)

class Girl(models.Model):
nick = models.CharField(max_length=32, null=True)

      class Love(models.Model):
       b = models.ForeignKey("Boy", null=True)
       g = models.ForeignKey("Girl", null=True)

       class Meta:
        unique_together = [
         ('b', 'g')
        ]
     views.py:
      ### 1. 查询和勾洋约会的姑娘
      # res = models.Boy.objects.filter(name='勾洋').first()
      # # print(res) ### Boy object
      # ### 反向查询 love中的相亲记录
      # love_list = res.love_set.all() ## <QuerySet [<Love: Love object>, <Love: Love object>]>
      # for obj in love_list:
      #     ### 正向查询 girl表中的nick
      #     print(obj.g.nick)

      #### 2.查询和勾洋约会的姑娘
      # res = models.Love.objects.filter(b__name='勾洋').all()
      # print(res) ## <QuerySet [<Love: Love object>, <Love: Love object>]>
      # for obj in res:
      #     print(obj.g.nick)

      ### 3.查询和勾洋约会的姑娘
      res = models.Love.objects.filter(b__name='勾洋').values("g__nick")
      print(res)

    django：
     通过 ManyToManyField() 来生成第三张表
     models.py:
      class Boy(models.Model):
       name = models.CharField(max_length=32, null=True)
       g = models.ManyToManyField('Girl', null=True)

      class Girl(models.Model):
       nick = models.CharField(max_length=32, null=True)
     views.py:
      ### django
      ### 添加
      obj = models.Boy.objects.filter(name='谢增城').first()
      # print(obj)### Boy object
      # obj.g.add(3)
      # obj.g.add(*[1,2])

### 重置
# obj.g.set([4])

      ### 查询
      # obj = models.Boy.objects.filter(name='谢增城').first()
      # res = obj.g.all()
      # print(res) ## <QuerySet [<Girl: Girl object>, <Girl: Girl object>, <Girl: Girl object>]>
      # for obj in res:
      #     print(obj.nick)

      ## 删除
      obj = models.Boy.objects.filter(name='谢增城').first()
      obj.g.clear()

    应该使用哪个？
     注意： ManyToManyField 只能生成两个字段（boy_id 和 girl_id）
     根据自己的业务逻辑去写


  e.增
   ### 插入一条数据
   models.xxx.objects.create(name='xxx')

   ### 插入多条数据
   obj = [
    models.UserInfo(name='zekai', age=12, ut_id=2),
    models.UserInfo(name='xxxxx', age=13, ut_id=2),
    models.UserInfo(name='dsadsa', age=14, ut_id=1),
    models.UserInfo(name='gfdgfdg', age=24, ut_id=2),
    models.UserInfo(name='tretre', age=45, ut_id=3),
    models.UserInfo(name='gfdgfd', age=42, ut_id=2),
   ]
   models.UserInfo.objects.bulk_create(obj)

  f.删
   models.xxxx.objects.all().delete()
   models.xxxx.objects.filter(name='kkk').delete()

   ps:
    ut = models.ForeignKey("UserType", null=True, on_delete=models.CASCADE)
    CASCADE: 设置级联删除
    SET_NULL : 取消级联删除

  g.改

   models.userinfo.objects.filter(xxxx).update()

2. Xss攻击

  全程：跨站脚本(js)攻击

   原因：
    用户输入的内容不可控

     <script>1.获取用户的cookie 2. 发送这个cookie到黑客的数据库</script>
  views.py:

   msg = []
   def comment(request):
    if request.method == 'GET':
     return render(request, "comment.html")
    else:
     comment = request.POST.get('comment')
     msg.append(comment)
     return render(request, "comment.html")

   def show(request):
    return render(request, 'show.html', {"msg":msg})

  comment.html:
   <form action="/comment/" method="post">
    <input type="text" name="comment">
    <input type="submit" value="提交">
   </form>

  show.html:
       <ul>
     {% for item in msg %}
      <li>{{ item | safe }}</li>
     {% endfor %}
    </ul>

posted on 2019-07-16 18:52 郝俊连城阅读(117) 评论(0) 编辑收藏举报