框架----Django框架知识点整理

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一、cbv

1 cbv(class-base-view)    基于类的视图
2 fbv(func-base-view)     基于函数的视图

a.基本演示

技术分享
1 urlpatterns = [
2    
3     url(r^login.html$, views.Login.as_view()),
4 ]
urls.py
技术分享
 1 from django.views import View
 2 
 3 class Login(View):
 4     """
 5     get       查
 6     post      创建
 7     put       更新
 8     delete    删除
 9     """
10     def dispatch(self, request, *args, **kwargs):
11         print(before)
12         obj = super(Login,self).dispatch(request,*args,**kwargs)
13         print("after")
14         return obj
15 
16     def get(self,request):
17         return render(request,"login.html")
18 
19     def post(self,request):
20         print(request.POST)
21 
22         return HttpResponse("Login.post")
23 
24 view.py
views.py

二、分页

a.Django分页

1 #浏览器访问
2 http://127.0.0.1:8000/index.html/?page=9
技术分享
1 urlpatterns = [
2  
3     #django分页
4     url(r^index, views.index),
5 ]
urls
技术分享
 1 #django 分页
 2 from django.core.paginator import Paginator,Page,PageNotAnInteger,EmptyPage
 3 def index(request):
 4     current_page = request.GET.get("page")
 5     user_list = models.User_info.objects.all()
 6     paginator = Paginator(user_list,10)  #每页显示10条
 7 
 8     """
 9     # count:    数据总个数
10     # num_pages:总页数
11     # page_range:总页数的索引范围,如: (1,10),(1,200)
12     # page:     page对象
13     """
14     try:
15         posts = paginator.page(current_page)   #当前页
16     except PageNotAnInteger as e:   #http://127.0.0.1:8000/index.html/?page=qqq 处理这种异常
17         posts = paginator.page(1)
18     except EmptyPage as e:  #http://127.0.0.1:8000/index.html/?page=-10  捕获这种异常
19         posts = paginator.page(1)
20 
21 
22     """
23     # has_next              是否有下一页
24     # next_page_number      下一页页码
25     # has_previous          是否有上一页
26     # previous_page_number  上一页页码
27     # object_list           分页之后的数据列表
28     # number                当前页
29     # paginator             paginator对象
30     """
31 
32     return render(request,"index.html",{"posts":posts})
33 
34 views.py
views.py
技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <h1>用户列表</h1>
 9     <ul>
10         {% for row in posts.object_list %}
11             <li>{{ row.name }}</li>
12         {% endfor %}
13     </ul>
14     <div>
15         {% if posts.has_previous %}
16             <a href="/index.html/?page={{ posts.previous_page_number }}">上一页</a>
17         {% endif %}
18 
19         {% for num in posts.paginator.page_range %}
20             <a href="/index.html/?page={{ num }}">{{ num }}</a>
21         {% endfor %}
22 
23         {% if posts.has_next %}
24             <a href="/index.html/?page={{ posts.next_page_number }}">下一页</a>
25         {% endif %}
26     </div>
27 
28 </body>
29 </html>
30 
31 index.html
index.html

b.自定义分页

1 #浏览器访问
2 http://127.0.0.1:8000/custom/?page=6
技术分享
1 urlpatterns = [
2 
3     #自定义分页
4     url(r^custom/, views.custom),
5 ]
urls
技术分享
 1 from utils.pager import PageInfo
 2 #自定义分页
 3 def custom(request):
 4 
 5     #总页数
 6     all_count = models.User_info.objects.all().count()
 7 
 8     #用户当前想要访问的页码
 9     current_page = request.GET.get("page")
10     page_info = PageInfo(current_page,all_count,10,"/custom",11)
11 
12     user_list = models.User_info.objects.all()[page_info.start():page_info.end()]
13 
14     return render(request,"custom.html",{"user_list":user_list,"page_info":page_info})
15 
16 views.py
views.py
技术分享
 1 class PageInfo(object):
 2 
 3     def __init__(self,current_page,all_count,per_page,base_url,show_page=11):
 4 
 5         #如果传值错误进入第一页
 6         try:
 7             self.current_page = int(current_page)
 8         except Exception as e:
 9             self.current_page = 1
10         self.per_page = per_page            #每页显示的个数
11 
12 
13         a,b = divmod(all_count,per_page)    #页数  余数
14         if b:
15             a = a + 1
16         self.all_page = a                   #总页码
17         self.show_page = show_page
18         self.base_url = base_url
19 
20     def start(self):
21         # 1  0: 10
22         # 2  10:20
23         # 3  20:30
24         return (self.current_page-1) * self.per_page
25 
26     def end(self):
27         return self.current_page * self.per_page
28 
29     def pager(self):
30 
31         page_list = []
32 
33         half = int((self.show_page-1)/2)
34 
35         if self.all_page < self.show_page:
36             begin = 1
37             stop = self.all_page + 1
38         else:
39             if self.current_page < half:
40                 begin = 1
41                 stop = self.show_page + 1
42             else:
43                 if self.current_page + half > self.all_page:
44                     begin = self.all_page - 10 +1
45                     stop = self.all_page + 1
46                 else:
47                     begin = self.current_page - half
48                     stop = self.current_page + half +1
49 
50         if self.current_page <=1:
51             prev = "<li><a href=‘#‘>上一页</a></li>"
52         else:
53             prev = "<li><a href=‘%s/?page=%s‘>上一页</a></li>"%(self.base_url,self.current_page - 1)
54 
55         page_list.append(prev)
56 
57 
58 
59         for i in range(begin,stop):
60             if i ==  self.current_page:
61                 temp = "<li class=‘active‘><a href=‘/custom/?page=%s‘>%s</a></li>"%(i,i)
62             else:
63                 temp = "<li><a href=‘%s/?page=%s‘>%s</a></li>"%(self.base_url,i,i)
64             page_list.append(temp)
65 
66 
67         if self.current_page >= self.all_page:
68             nex = "<li><a href=‘#‘>下一页</a></li>"
69         else:
70             nex = "<li><a href=‘%s/?page=%s‘>下一页</a></li>" % (self.base_url,self.current_page + 1)
71 
72         page_list.append(nex)
73 
74         return "".join(page_list)
75 
76 utils/pager.py
utils/pager.py
技术分享
 1 from django.db import models
 2 
 3 # Create your models here.
 4 
 5 
 6 class User_type(models.Model):
 7     uid = models.BigAutoField(primary_key=True)
 8     title = models.CharField(max_length=32)
 9 
10 class User_info(models.Model):
11     name = models.CharField(max_length=32)
12     age = models.CharField(max_length=32)
13     ut = models.ForeignKey("User_type")
14 
15 models.py
models.py
技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6     <link rel="stylesheet" href="/static/plugins/bootstrap-3.3.7-dist/css/bootstrap.css" />
 7 </head>
 8 <body>
 9 
10     {% for row in user_list %}
11         <li>{{ row.name }}</li>
12     {% endfor %}
13 
14 
15     <nav aria-label="Page navigation">
16       <ul class="pagination">
17         {{ page_info.pager |safe }}
18 
19       </ul>
20     </nav>
21 </body>
22 </html>
23 
24 custom.html
custom.html

三、ORM正反向连表操作

技术分享
 1 #ORM正反向连表操作
 2 - models
 3 from django.db import models
 4 
 5 class Foo(models.Model):
 6    """
 7    第三个表
 8    """
 9    caption = models.CharField(max_length=16)
10    
11 
12 class UserType(models.Model):
13     """
14     用户类型
15     """
16     title = models.CharField(max_length=32)
17     fo = models.ForeignKey(Foo)
18 
19     
20 class UserInfo(models.Model):
21     """
22     用户表
23     """
24     name = models.CharField(max_length=16)
25     age = models.IntegerField()
26     ut = models.ForeignKey(UserType)
27     
28     
29 - views
30     ----#跨表(正向操作)---UserInfo----含ForeignKey字段   PS: 一个用户只有一个用户类型
31         # 获取
32         # QuerySet[obj,obj,obj]
33         result = models.UserInfo.objects.all()
34         for obj in result:
35             print(obj.name,obj.age,obj.ut_id,obj.ut.title,obj.ut.fo.caption)
36             
37     ----#跨表(反向操作)---UserType----不含ForeignKey字段   PS: 一个用户类型下可以有很多用户
38     
39         obj = models.UserType.objects.all().first()
40         print(用户类型,obj.id,obj.title)
41         for row in obj.userinfo_set.all():       #使用的是与之关联的表名小写加_set.all()这个方法取到所有东西
42         print(row.name,row.age)
View Code

四、数据获取多个数据时(注意3种情况的不同之处<跨表查询、跨表取值>)

技术分享
 1  # 数据获取多个数据时(注意3种情况的不同之处<跨表查询、跨表取值>)
 2     1. [obj,obj,obj,]      # .all()和.filter()拿到的结果是QuerySet对象
 3     models.UserInfo.objects.all()
 4     models.UserInfo.objects.filter(id__gt=1)
 5     result = models.UserInfo.objects.all()
 6     for item in result:
 7         print(item.name,item.ut.title)    # 取值方式:item.name,item.ut.title   可以跨表  
 8         
 9 
10     2. [{id:1,name:fd},{id:1,name:fd},{id:1,name:fd},]   # .values()拿到的结果是字典
11     models.UserInfo.objects.all().values(id,name)
12     models.UserInfo.objects.filter(id__gt=1).values(id,name)
13     #无法跨表
14     result = models.UserInfo.objects.all().values(id,name)
15     for item in result:
16         print(item[id],item[name])   # 取值方式:item[‘id‘],item[‘name‘]   #无法跨表 
17     #跨表  使用__(双下划线)
18     result = models.UserInfo.objects.all().values(id,name,"ut__title")    # 这里查询时跨表使用的是ut__title  双下划线
19     for item in result:
20         print(item[id],item[name],item[ut__title])   # 跨表取值时也用的是双下滑线__
21         
22 
23 
24     3. [(1,df),(2,df)]     # .values_list()拿到的结果是元组
25     models.UserInfo.objects.all().values_list(id,name)
26     models.UserInfo.objects.filter(id__gt=1).values_list(id,name)
27     #无法跨表
28     result = models.UserInfo.objects.all().values_list(id,name)
29     for item in result:
30         print(item[0],item[1])   # 取值方式: item[0],item[1]   #无法跨表
31     #跨表  使用__(双下划线)
32     result = models.UserInfo.objects.all().values_list(id,name,"ut__title")  # 这里要跨表使用的是ut__title  双下划线
33     for item in result:
34         print(item[0],item[1],item[2])     # 跨表取值时用的是下标    
View Code

五、CSRF(跨站请求伪造)

CSRF(Cross-site request forgery)跨站请求伪造,通常缩写为CSRF或者XSRF,是一种对网站的恶意利用。尽管听起来像跨站脚本(XSS)
    但它与XSS非常不同,XSS利用站点内的信任用户,而CSRF则通过伪装来自受信任用户的请求来利用受信任的网站。
 
理解:csrf_token防止从别的网站向自己网站发post请求, 客户来访问网站,网站会向客户发送随机字符串,然后客户带随机字符串发送post请求
        只有带随机字符串来,网站才认,一般是post请求才要求带随机字符串,其它网站第一次来不会带随机字符串。

a. django开启csrf

MIDDLEWARE = [
    django.middleware.csrf.CsrfViewMiddleware,
]

b.HTML中使用

{% csrf_token %}       #只要写上{% csrf_token %} 会有一个隐藏的input随机字符串,在cookie也有一个随机的字符串,form表单提交数据时,一般会使用
{{ csrf_token }}       #生成随机的字符串

c.django中设置防跨站请求伪造功能有分为全局和局部

#局部
 
from django.views.decorators.csrf import csrf_exempt,csrf_protect
 
@csrf_protect   settings中没有设置全局中间件,为当前函数强制设置防跨站请求伪造功能。
@csrf_exempt    settings中设置了全局中间件,取消当前函数防跨站请求伪造功能。
技术分享
 1 #fbv
 2 
 3 @csrf_protect
 4 def func(object):
 5     pass
 6 
 7 #cbv
 8 
 9 from django.views import View
10 from django.utils.decorators import method_decorator
11 
12 @method_decorator(csrf_exempt,name="dispatch")
13 class foo(View)
14     pass
15 
16 fbv和cbv应用装饰器
fbv和cbv应用装饰器
技术分享
 1 #方式一 类上加装饰器:
 2 
 3 def wrapper(func):
 4     def inner(*args,**kwargs):
 5         return func(*args,**kwargs)
 6     return inner
 7 
 8 @method_decorator(wrapper,name="get")
 9 @method_decorator(wrapper,name="post")
10 class foo(View):
11 
12     def get(self,request):
13         pass
14 
15     def post(self,request):
16         pass
17 
18 
19 
20 #方式二 类上“dispatch”加装饰器:
21 
22 def wrapper(func):
23     def inner(*args,**kwargs):
24         return func(*args,**kwargs)
25     return inner
26 
27 @method_decorator(wrapper,name="dispatch")
28 class foo(View):
29 
30     def dispatch(self,request,*args,**kwargs):
31         return xxx
32 
33     def get(self,request):
34         pass
35 
36     def post(self,request):
37         pass
38 
39 
40 #方式三 方法上加装饰器:
41 
42 def wrapper(func):
43     def inner(*args,**kwargs):
44         return func(*args,**kwargs)
45     return inner
46 
47 class foo(View):
48 
49 
50     @method_decorator(wrapper)
51     def get(self,request):
52         pass
53 
54     def post(self,request):
55         pass
56 
57 cbv应用其它装饰器
cbv应用其它装饰器

d. Ajax提交数据 携带CSRF 

1. 通过获取隐藏的input标签中的字符串,放置在data中发送

技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <form method="POST" action="/csrf1.html">
 9         {% csrf_token %}
10         <input id="user" type="text" name="user"/>
11         <a onclick="submitForm();">Ajax提交</a>
12     </form>
13 
14     <script src="/static/jquery-1.12.4.js"></script>
15     <script>
16         function submitForm() {
17             var csrf = $(input[name="csrfmiddlewaretoken"]).val();
18             var user = $("#user").val();
19             $.ajax({
20                 url:/csrf1.html,
21                 type:POST,
22                 data:{"user":user,"csrfmiddlewaretoken":csrf},
23                 success:function (arg) {
24                     console.log(arg);
25                 }
26 
27             })
28         }
29     </script>
30 
31 
32 
33 </body>
34 </html>
35 
36 csrf1.html
csrf1.html
技术分享
1 urlpatterns = [
2 
3     url(r^csrf1.html, views.csrf1),
4 ]
urls.py
技术分享
1 def csrf1(request):
2 
3     if request.method == GET:
4         return render(request,csrf1.html)
5     else:
6         return HttpResponse(ok)
views.py

2. 通过获取返回的cookie中的字符串,放置在请求头中发送 

通过在console中 document.cookie可以获取 csrftoken=JPv1gIdrBiAlK2RCrgFs0OKwsncPXvwPfMhEWIVzMdMFymIayiuGu2GkBAu57moL
但需要切割字符串,通过引入jquery.cookie.js对cookie操作,使用$.cookie("csrftoken")
技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <form method="POST" action="/csrf1.html">
 9         {% csrf_token %}
10         <input id="user" type="text" name="user"/>
11         <a onclick="submitForm();">Ajax提交</a>
12     </form>
13 
14     <script src="/static/jquery-1.12.4.js"></script>
15     <script src="/static/jquery.cookie.js"></script>
16     <script>
17         function submitForm() {
18             var token = $.cookie("csrftoken");
19             var user = $("#user").val();
20             $.ajax({
21                 url:/csrf1.html,
22                 type:POST,
23                 headers:{"X-CSRFToken":token},
24                 data:{"user":user},
25                 success:function (arg) {
26                     console.log(arg);
27                 }
28 
29             })
30         }
31     </script>
32 
33 
34 
35 
36 
37 </body>
38 </html>
39 
40 csrf1.html
csrf1.html

六、Django框架最最最最最最基础的3+5基本使用步骤 ?????

技术分享
1,创建项目文件夹
   在终端Terminal执行命令:
        django-admin startproject 项目名

  
2,配置3个地方
  (1)模板路径配置
      TEMPLATES = [
        {
            BACKEND: django.template.backends.django.DjangoTemplates,
            DIRS: [os.path.join(BASE_DIR,templates)],      # 这一步
            APP_DIRS: True,
            OPTIONS: {
                context_processors: [
                    django.template.context_processors.debug,
                    django.template.context_processors.request,
                    django.contrib.auth.context_processors.auth,
                    django.contrib.messages.context_processors.messages,
                ],
            },
        },
    ]
  (2) 静态文件配置
        STATIC_URL = /static/
        STATICFILES_DIR = (
            os.path.join(BASE_DIR,static)
        )
        
  (3) # ‘django.middleware.csrf.CsrfViewMiddleware‘,  注释这一行

   
  
3,Django框架5步
  在终端Terminal执行命令创建app模块:
         python manage.py startapp 模块名


   (1)连接数据库
        DATABASES = {
            default: {
                ENGINE: django.db.backends.mysql,
                NAME: "studentPro",
                USER:yangzai,
                PASSWORD:[email protected],
                HOST:mypy.me,
                PORT:3306,
            }
        }

   (2)导入pymysql
     在__init__中写入
       import pymysql
       pymysql.install_as_MySQLdb()

   (3)创建model
      from django.db import models
       class UserInfo(models.Model):
           id = 
           name = 
           password =      

   (4)注册模块
      INSTALLED_APPS = [
        django.contrib.admin,
        django.contrib.auth,
        django.contrib.contenttypes,
        django.contrib.sessions,
        django.contrib.messages,
        django.contrib.staticfiles,
        app01    -----这一步
      ]
   

   (5)初始化数据库
        python manage.py makemigrations   --先执行
      python manage.py migrate          --后执行
基本使用步骤

七、Django框架里面return的3种返回

技术分享
return render()        - 返回页面
  - return render(request,index.html,{std_list:std_list})
  3个参数含义:
  request:用户的请求信息
  index.html:需要返回的模板html页面
  {std_list:std_list}:存放模板文件里面要被替换的占位符所对应的值


  
return HttpResponse()  - 返回字符串
  - return HttpResponse(json.dumps(ret))

  
return redirect()      - 返回url请求
  - return redirect(/teachers/)

  
提示点:redirect,href,action,这3中url请求,都要在地址前加/斜杠
   例子:return redirect(/classes.html)
        <a href="/edit_class/{{ row.id }}.html">
        <form method="POST" action="/edit_class/{{ id }}.html">


return的3中返回
return的3中返回

八、cookie

a. 简单应用

技术分享
 1 def login(request):
 2     if request.method=="GET":
 3         return render(request,"login.html")
 4     else:
 5         name = request.POST.get("name")
 6         password = request.POST.get("password")
 7         if name == "alex" and password == "123":
 8             obj = redirect("/classes/")
 9             obj.set_cookie("ticket","123456",max_age=10)
10             return obj
11         else:
12             return redirect("/login/")
13 
14 
15 
16 def classes(request):
17     sk = request.COOKIES
18     print(sk)
19     if not sk:
20         return redirect("/login/")
View Code

b. 过期时间的两种格式

 1 方式一:
 2 obj.set_cookie("ticket","123456",max_age=10)
 3  
 4 方式二:
 5 import datetime
 6 from datetime import timedelta     #时间的加减
 7 ct = datetime.datetime.utcnow()   #获取当前日期
 8 v= timedelta(seconds=10)   #10秒
 9 value = ct + v
10  
11 obj.set_cookie("ticket","123456",expires=value)

c. 限制路径

1 obj.set_cookie("ticket","123456",max_age=10,path="/")   #所有路径都可以访问
2  
3 obj.set_cookie("ticket","123456",max_age=10,path="/class")   #只有class访问

d. cookie签名

1 #
2 obj.set_signed_cookie("ticket","123456",salt="abc")
3  
4 #
5 sk = request.get_signed_cookie("ticket",salt="abc")

九、session

1 流程:客户登录网址,验证成功后,服务端生成一个随机字符串和随机字符串对应的键值,然后把随机字符串通过cookie发送给客户端
2      客户端拿着随机字符串通过cookir再次登陆,服务端拿着随机字符串和保存在本地的数据对应,以确定用户的登录状态
技术分享
Cookie是什么?
    保存在客户端浏览器上的键值对
Session是什么?
    保存在服务端的数据(本质是键值对)
    {
        “aaaaa":{‘id‘:1,‘name‘:‘于浩‘,email=‘xxxx‘}
        "bbbbb":{id:2,name:陈涛,email=0000}
    }
    应用:依赖cookie
    作用:保持会话(Web网站)
    好处:敏感信息不会直接给客户端
    
    梳理:
        1. 保存在服务端的数据(本质是键值对)
        2. 配置文件中:
            - 存储位置
            - 超时时间、每次刷新更新时间
session是什么

a. 简单示例

用户访问http://127.0.0.1:8000/login/
技术分享
urlpatterns = [

    url(r^index/, views.index),
    url(r^login/, views.login),
]
urls
技术分享
 1 def login(request):
 2     if request.method == GET:
 3         return render(request,login.html)
 4     else:
 5         u = request.POST.get(user)
 6         p = request.POST.get(pwd)
 7         obj = models.UserAdmin.objects.filter(username=u,password=p).first()
 8         if obj:
 9             # 1. 生成随机字符串
10             # 2. 通过cookie发送给客户端
11             # 3. 服务端保存
12             # {
13             #   随机字符串1: {‘username‘:‘alex‘,‘email‘:x‘‘...}
14             # }
15             request.session[username] = obj.username
16             return redirect(/index/)
17         else:
18             return render(request,login.html,{msg:用户名或密码错误})
19 
20 
21 def index(request):
22     # 1. 获取客户端端cookie中的随机字符串
23     # 2. 去session中查找有没有随机字符
24     # 3. 去session对应key的value中查看是否有 username
25     v = request.session.get(username)
26     if v:
27         return HttpResponse(登录成功:%s %v)
28     else:
29         return redirect(/login/)
30 
31 views.py
views.py
技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8 
 9 <form action="/login/" method="POST">
10     <input type="text" name="user">
11     <input type="text" name="pwd">
12     <input type="submit" value="提交">{{ msg }}
13 </form>
14 
15 
16 </body>
17 </html>
18 
19 login.html
login.html
技术分享
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8 
 9     <h1>index page</h1>
10 
11 </body>
12 </html>
13 
14 index.html
index.html

十、URL(路由配置系统)

 1 URL配置(URLconf)就像Django 所支撑网站的目录。它的本质是URL与要为该URL调用的视图函数之间的映射表;你就是以这种方式告诉Django,对于这个URL调用这段代码<br>对于那个URL调用那段代码
 2 
 3     urlpatterns = [
 4          url(正则表达式, views视图函数,参数,别名),
 5 ]
 6  
 7 参数说明:
 8  
 9     一个正则表达式字符串
10     一个可调用对象,通常为一个视图函数或一个指定视图函数路径的字符串
11     可选的要传递给视图函数的默认参数(字典形式)
12     一个可选的name参数

1. 单一路由对应

1 url(r^index$, views.index)

2. 基于正则的路由

1 #  $
2 url(r^index/(\d{4})$,views.index)
3  
4 #无命名分组
5 url(r^index/(\d{4})/(\d{2}),views.index)
6  
7 #有命名分组
8 url(r^index/(?P<year>\d{4})/(?P<month>\d{2}),views.index)
技术分享
 1 ############################无命名
 2 
 3 #-----------------() 相当于传参数 
 4 
 5 url(r^index/(\d{4}),views.index)
 6     
 7     def index(request,arg):
 8         return HttpResponse(arg)    
 9 
10 #url访问http://127.0.0.1:8000/index/1113
11 
12 #-----------------() 接受两个参数
13 
14 url(r^index/(\d{4})/(\d{2}),views.index)
15 
16     def index(request,arg,arg1):
17         return HttpResponse("year: %s month: %s"%(arg,arg1))
18 
19 #url访问http://127.0.0.1:8000/index/2017/06
20     year: 2017 month: 06
21 
22 
23 
24 ############################有命名
25 url(r^index/(?P<year>\d{4})/(?P<month>\d{2}),views.index)
26 
27     def index(request,year,month):
28         return HttpResponse("year: %s month: %s"%(year,month))
29 
30 #url访问http://127.0.0.1:8000/index/2017/06
31     year: 2017 month: 06
32 
33 有无命名分组 演示
有无命名分组 演示

3. 为路由映射设置名称

1 #应用一:
2 url(r^index,views.index,name="arg")
3  
4 {{ url "arg" }}     匹配index
5 {{ url "arg" i}}
6  
7 #应用二:
8 reverse反向获取url
技术分享
 1 ##############根据url反生成名字
 2 from django.shortcuts import reverse
 3 
 4 url(r^index,views.index,name="arg")
 5 
 6 def index(request):
 7     v = reverse("arg")
 8     print(v)
 9     return HttpResponse()
10 
11  #用户访问http://127.0.0.1:8000/index
12  /index
13 
14 
15 ##############根据url改变url
16 
17 url(r^index/(\d+)/,views.index,name="n1")
18 
19 def index(request,xx):
20 
21     v = reverse(n1,args=(1,))
22     print(v)
23     return HttpResponse("...")
24 
25  #访问http://127.0.0.1:8000/index/222/
26  /index/1/
27 
28 reverse示例 演示
reverse示例 演示

4. 路由分发

1 url(r^app01/,include("app01.urls"))
2 url(r^app02/,include("app02.urls"))
3  
4 #没有匹配成功,返回默认页面
5 url(r^,include("views.default"))

十一、Model

a. 创建表 

技术分享
 1 from django.db import models
 2 
 3 
 4 class User_type(models.Model):
 5     uid = models.BigAutoField(primary_key=True)
 6     title = models.CharField(max_length=32)
 7 
 8 class User_info(models.Model):
 9     name = models.CharField(max_length=32)
10     age = models.CharField(max_length=32)
11     ut = models.ForeignKey("User_type")
12 
13 
14 python3 manage.py makemigrations
15 
16 python3 manage.py migrate
17 
18 
19 ---------------------其它---------------------
20 
21 class part(models.Model):
22     cid = models.BigAutoField(primary_key=True)
23     title = models.CharField(max_length=32,null=False)
24 
25 
26 class student(models.Model):
27     sid = models.BigAutoField(primary_key=True)
28     name = models.CharField(max_length=32,null=False)
29     pub_data=models.DateField()
30     age = models.IntegerField(default=18)
31     # 新增加的列 如果原先表里有值,写default
32     ug = models.ForeignKey("part",null=True) #如果新增加外键,加null=True
View Code

b. ORM操作

技术分享
 1 #
 2 # models.User_type.objects.create(title="黑金用户")
 3     
 4 # obj = models.User_type(title="小白用户")
 5 # obj.save()
 6 
 7 
 8 #
 9 #models.User_type.objects.filter(title="小白用户").delete()  # 删除指定条件的数据
10 
11 #
12 #models.User_type.objects.filter(title="黑金用户").update(title="黑卡用户")    # 修改指定条件的数据
13 
14 #
15 # models.User_type.objects.get(title="大白用户")      # 获取单条数据,不存在则报错(不建议)
16 # models.User_type.objects.all()                     # 获取全部
17 # models.User_type.objects.filter(title="小白用户")   # 获取指定条件的数据
18 # models.User_type.objects.exclude(title="黄金用户")     # 排除指定条件的数据
19 
20 基本增删改查
基本增删改查
技术分享
 1 # 获取个数
 2 
 3 models.User_info.objects.filter(age=18).count()   
 4 
 5 
 6 # 大于 小于
 7 
 8 # models.Tb1.objects.filter(id__gt=1)               # 获取id大于1的值
 9 # models.Tb1.objects.filter(id__gte=1)              # 获取id大于等于1的值
10 # models.Tb1.objects.filter(id__lt=10)              # 获取id小于10的值
11 # models.Tb1.objects.filter(id__lte=10)             # 获取id小于10的值
12 # models.Tb1.objects.filter(id__gt=1,id__lt=10)     # 获取id大于1 且 小于10的值
13 
14 
15 
16 #in
17 
18 models.User_info.objects.filter(age__in=[19])        #  in 
19 models.User_info.objects.exclude(age__in=[19])        #  not in
20 
21 
22 # isnull
23 
24 models.User_info.objects.filter(age__isnull=True)    # age列为不为空
25 models.User_info.objects.filter(age__isnull=False)    # age列是不是 不为空
26 
27 
28 # contains
29 
30 # models.Tb1.objects.filter(name__contains="ven")
31 # models.Tb1.objects.filter(name__icontains="ven")  # icontains大小写不敏感
32 # models.Tb1.objects.exclude(name__icontains="ven")
33 
34 
35 
36 # range
37 
38 # models.Tb1.objects.filter(id__range=[1, 5])   # 范围bettwen and
39 
40 
41 #开始 结束
42 
43 # startswith,istartswith, endswith, iendswith
44 
45 
46 
47 #order_by 
48 
49 #models.User_info.objects.all().order_by("id")                # asc
50 #models.User_info.objects.all().order_by("-id")                # desc
51 
52 # models.Tb1.objects.filter(name=‘seven‘).order_by(‘id‘)    # asc
53 # models.Tb1.objects.filter(name=‘seven‘).order_by(‘-id‘)   # desc
54 
55 
56 
57 #group by     #后面出现filter代表having
58 
59 from django.db.models import Count
60 #models.User_info.objects.values("name","age").annotate()                    #没有起作用
61 #SELECT "app01_user_info"."name", "app01_user_info"."age" FROM "app01_user_info"
62 
63 #models.User_info.objects.values("age").annotate(xxx=Count("age"))
64 #SELECT "app01_user_info"."age", COUNT("app01_user_info"."age") AS "xxx" FROM "app01_user_info" GROUP BY "app01_user_info"."age"
65 
66 #models.User_info.objects.values("age").annotate(xxx=Count("age")).filter(xxx__gt=2)        #年龄相同次数大于2的查出来
67 #SELECT "app01_user_info"."age", COUNT("app01_user_info"."age") AS "xxx" FROM "app01_user_info" GROUP BY "app01_user_info"."age" HAVING COUNT("app01_user_info"."age") > 2
68 
69 
70 #注意两次filter  第一次代表where  第二次代表having
71 
72 #models.User_info.objects.filter(id__gt=2).values("age").annotate(xxx=Count("age")).filter(xxx__gt=2)        
73 #SELECT "app01_user_info"."age", COUNT("app01_user_info"."age") AS "xxx" FROM "app01_user_info" WHERE "app01_user_info"."id" > 2 GROUP BY "app01_user_info"."age" HAVING COUNT("app01_user_info"."age") > 2
74 
75 常用方法
常用方法
技术分享
 1 # F
 2 
 3 # from django.db.models import F
 4 # models.User_info.objects.all().update(age=F("age")+5)        # age列加5
 5 
 6 
 7 # Q
 8 
 9 # 方式一:
10 # Q(nid__gt=10)
11 # Q(nid=8) | Q(nid__gt=10)
12 # Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption=‘root‘)
13 
14 
15 #-------------------------------以下三种查找方式相同效果
16 
17 # obj = models.User_info.objects.filter(id=307,name="egon")
18 
19 # condition ={
20 #     ‘id‘:307,
21 #     ‘name‘:‘egon‘,
22 # }
23 # obj = models.User_info.objects.filter(**condition)
24 
25 #obj = models.User_info.objects.filter(Q(id=307) & Q(name="egon"))
26 ---------------------------------
27 
28 
29 # 方式二:
30 
31 
32 # q1 = Q()
33 # q1.connector = ‘OR‘
34 # q1.children.append((‘id‘, 1))
35 # q1.children.append((‘id‘, 10))
36 # q1.children.append((‘id‘, 9))
37 
38 # q2 = Q()
39 # q2.connector = ‘OR‘
40 # q2.children.append((‘c1‘, 1))
41 # q2.children.append((‘c1‘, 10))
42 # q2.children.append((‘c1‘, 9))
43 
44 # q3 = Q()
45 # q3.connector = ‘AND‘
46 # q3.children.append((‘id‘, 1))
47 # q3.children.append((‘id‘, 2))
48 # q1.add(q3, ‘OR‘)
49 
50 # con = Q()
51 # con.add(q1, ‘AND‘)
52 # con.add(q2, ‘AND‘)
53 
54 #(id=1 or id=10 or id=9 or (id=1 and id=2)) and (c1=1 or c1=10 or c1=9)  #等于上面
55 
56 # models.Tb1.objects.filter(con)
57 
58 
59 # Q演示
60 condition_dict = {
61         k1:[1,2,3,4],
62         k2:[1,],
63         k3:[11,]
64 }
65 
66 con = Q()
67 for k,v in condition_dict.items():
68     q = Q()
69     q.connector = OR
70     for i in v:
71         q.children.append((id,1))
72     con.add(q,AND)
73 
74 models.User_info.objects.filter(con)
75 
76 F Q 演示
F Q 演示

c. 多对多操作

方式一:通过外键创建第三张表

 1 class Boy(models.Model):
 2     name = models.CharField(max_length=32)
 3  
 4 class Girl(models.Model):
 5     nick = models.CharField(max_length=32)
 6  
 7 class Love(models.Model):
 8     b = models.ForeignKey("Boy")
 9     g = models.ForeignKey("Girl")
10      
11     class Meta:
12         unique_together = [
13             ("b","g"),
14         ]
技术分享
 1 #表里插入数据
 2 
 3 objs = [
 4         models.Boy(name=方少伟),
 5         models.Boy(name=游勤斌),
 6         models.Boy(name=于浩),
 7         models.Boy(name=陈涛),
 8 ]
 9 models.Boy.objects.bulk_create(objs,4)
10 
11 result = [
12     models.Girl(nick=于浩姐姐),
13     models.Girl(nick=景甜),
14     models.Girl(nick=刘亦非),
15     models.Girl(nick=苍老师),
16 ]
17 models.Girl.objects.bulk_create(result, 4)
18 
19 models.Love.objects.create(b_id=1,g_id=1)
20 models.Love.objects.create(b_id=1,g_id=2)
21 models.Love.objects.create(b_id=1,g_id=3)
22 models.Love.objects.create(b_id=2,g_id=4)
23 
24 
25 ###################   查找和我有关系的女孩  四种方式 ################
26 
27 
28 obj = models.Boy.objects.filter(name="方少伟").first()
29 love_list = obj.love_set.all()
30 for row in love_list:
31    print(row.g.nick)
32 
33 love_list = models.Love.objects.filter(b__name="方少伟")
34 for row in love_list:
35     print(row.g.nick)
36 
37 
38 #下面两个效果好
39 
40 love_list = models.Love.objects.filter(b__name="方少伟").values("g__nick")
41 for item in love_list:
42     print(item["g__nick"])   
43     
44 
45 
46 love_list = models.Love.objects.filter(b__name="方少伟").select_related("g")
47 for obj in love_list:
48     print(obj.g.nick)
49 
50 SQL演示
SQL演示

方式二:通过 ManyToManyField 创建第三张表

1 class Boy(models.Model):
2     name = models.CharField(max_length=32)
3     m = models.ManyToManyField("Girl")
4  
5 class Girl(models.Model):
6     nick = models.CharField(max_length=32)
技术分享
 1 obj = models.Boy.objects.filter(name="方少伟").first()
 2     # print(obj.id,obj.name)
 3 
 4     # obj.m.add(2)
 5     # obj.m.add(1,3)
 6     # obj.m.add(*[4,])
 7 
 8     # obj.m.remove(2)
 9     # obj.m.remove(1,3)
10     # obj.m.remove(*[4,])
11 
12     # obj.m.set([1,4,])
13 
14 
15     # girl_list = obj.m.all()
16     # girl_list = obj.m.filter(nick="苍老师")
17 
18 
19     # obj.m.clear()
20 
21 obj = models.Girl.objects.filter(nick="苍老师").first()
22 v = obj.boy_set.all()        
23 
24 SQL 演示
SQL 演示

方式三:通过 外键ManyToManyField 创建

 1 class Boy(models.Model):
 2     name = models.CharField(max_length=32)
 3     m = models.ManyToManyField("Girl",through="Love",through_fields=("b","g",))
 4  
 5 class Girl(models.Model):
 6     nick = models.CharField(max_length=32)
 7  
 8 class Love(models.Model):
 9     b = models.ForeignKey("Boy")
10     g = models.ForeignKey("Girl")
11  
12     class Meta:
13         unique_together = [
14             ("b","g"),
15         ]
技术分享
1 obj = models.Boy.objects.filter(name="方少伟").first()
2 
3 #只可以查或清空
4 obj.m.clear()
5 
6 obj.m.all()
7 
8 SQL 操作
SQL 操作

d. 一对多

 1 正向:
 2     filter() values,values_list() -> 跨表  fk__xxx
 3     objs = all()
 4     for obj in objs:
 5         obj.fk.
 6 反向:
 7     filter() values,values_list() -> 跨表  表名称__xxx
 8     objs = all()
 9     for obj in objs:
10         obj.表名称_set.all() 

1.连表操作演示

技术分享
1 urlpatterns = [
2  
3     url(r^test/, views.test),
4 
5 ]
urls
技术分享
 1 class User_type(models.Model):
 2     uid = models.BigAutoField(primary_key=True)
 3     title = models.CharField(max_length=32)
 4 
 5 class User_info(models.Model):
 6     name = models.CharField(max_length=32)
 7     age = models.CharField(max_length=32)
 8     ut = models.ForeignKey("User_type")
 9 
10 models.py
models.py
技术分享
 1 def test(request):
 2     models.User_type.objects.create(title="普通用户")
 3     models.User_type.objects.create(title="白金用户")
 4     models.User_type.objects.create(title="黄金用户")
 5 
 6 
 7     models.User_info.objects.create(name="小鸡",age=18,ut_id=1)
 8     models.User_info.objects.create(name="小狗",age=18,ut_id=2)
 9     models.User_info.objects.create(name="小猫",age=18,ut_id=2)
10     models.User_info.objects.create(name="小雨",age=18,ut_id=3)
11     models.User_info.objects.create(name="大雨",age=18,ut_id=1)
12 
13     for i  in range(300):
14         name = "root" + str(i)
15         models.User_info.objects.create(name=name, age=18, ut_id=1)
16 
17     #正向操作
18     obj = models.User_info.objects.all().first()
19     print(obj.name,obj.age,obj.ut.title)
20 
21     #反向操作   obj.表名小写_set.all()
22     obj = models.User_type.objects.all().first()
23     for row in obj.user_info_set.all():
24         print(row.name,row.age)
25 
26     result = models.User_type.objects.all()
27     for item in result:
28         print(item.title,item.user_info_set.all())
29         print(item.user_info_set.filter(name="小雨"))
30 
31 
32     #字典格式
33     result = models.User_info.objects.all().values("id","name")
34     for row in result:
35         print(row)
36 
37     #字典格式查的时候跨表
38     result = models.User_info.objects.all().values("id","name","ut__title")
39     for row in result:
40         print(row["id"],row["name"],row["ut__title"])
41 
42 
43 
44 
45 
46     # 元组格式
47     # result = models.User_info.objects.all().values_list("id","name")
48     # for row in result:
49     #     print(row)
50 
51     return HttpResponse(".....")
52 
53 views.py
views.py

 十二、ORM操作

技术分享
 1 操作数据行:---------(在views中操作)
 2  3                  models.Tb1.objects.create(c1=xx, c2=oo)  增加一条数据,可以接受字典类型数据 **kwargs
 4                     obj = models.Tb1(c1=xx, c2=oo)
 5                     obj.save()
 6                     
 7  8                 models.Tb1.objects.filter(name=seven).delete()     # 删除指定条件的数据
 9                 
10 11                 models.Tb1.objects.filter(name=seven).update(gender=0)      # 将指定条件的数据更新,均支持 **kwargs
12                 obj = models.Tb1.objects.get(id=1)
13                 obj.c1 = 111
14                 obj.save()       # 修改单条数据
15                 
16 17                 models.Tb1.objects.get(id=123)         # 获取单条数据,不存在则报错(不建议)
18                 models.Tb1.objects.all()               # 获取全部
19                 models.Tb1.objects.filter(name=seven) # 获取指定条件的数据
基本增、删、改、查
技术分享
 1 # 获取个数
 2         #
 3         # models.Tb1.objects.filter(name=‘seven‘).count()
 4 
 5         # 大于,小于
 6         #
 7         # models.Tb1.objects.filter(id__gt=1)              # 获取id大于1的值
 8         # models.Tb1.objects.filter(id__gte=1)              # 获取id大于等于1的值
 9         # models.Tb1.objects.filter(id__lt=10)             # 获取id小于10的值
10         # models.Tb1.objects.filter(id__lte=10)             # 获取id小于10的值
11         # models.Tb1.objects.filter(id__lt=10, id__gt=1)   # 获取id大于1 且 小于10的值
12 
13         # in
14         #
15         # models.Tb1.objects.filter(id__in=[11, 22, 33])   # 获取id等于11、22、33的数据
16         # models.Tb1.objects.exclude(id__in=[11, 22, 33])  # not in
17 
18         # isnull
19         # Entry.objects.filter(pub_date__isnull=True)
20 
21         # contains
22         #
23         # models.Tb1.objects.filter(name__contains="ven")
24         # models.Tb1.objects.filter(name__icontains="ven") # icontains大小写不敏感
25         # models.Tb1.objects.exclude(name__icontains="ven")
26 
27         # range
28         #
29         # models.Tb1.objects.filter(id__range=[1, 2])   # 范围bettwen and
30 
31         # 其他类似
32         #
33         # startswith,istartswith, endswith, iendswith,
34 
35         # order by
36         #
37         # models.Tb1.objects.filter(name=‘seven‘).order_by(‘id‘)    # asc
38         # models.Tb1.objects.filter(name=‘seven‘).order_by(‘-id‘)   # desc
39 
40         # group by
41         #
42         # from django.db.models import Count, Min, Max, Sum
43         # models.Tb1.objects.filter(c1=1).values(‘id‘).annotate(c=Count(‘num‘))
44         # SELECT "app01_tb1"."id", COUNT("app01_tb1"."num") AS "c" FROM "app01_tb1" WHERE "app01_tb1"."c1" = 1 GROUP BY "app01_tb1"."id"
45 
46         # limit 、offset
47         #
48         # models.Tb1.objects.all()[10:20]
49 
50         # regex正则匹配,iregex 不区分大小写
51         #
52         # Entry.objects.get(title__regex=r‘^(An?|The) +‘)
53         # Entry.objects.get(title__iregex=r‘^(an?|the) +‘)
54 
55         # date
56         #
57         # Entry.objects.filter(pub_date__date=datetime.date(2005, 1, 1))
58         # Entry.objects.filter(pub_date__date__gt=datetime.date(2005, 1, 1))
59 
60         # year
61         #
62         # Entry.objects.filter(pub_date__year=2005)
63         # Entry.objects.filter(pub_date__year__gte=2005)
64 
65         # month
66         #
67         # Entry.objects.filter(pub_date__month=12)
68         # Entry.objects.filter(pub_date__month__gte=6)
69 
70         # day
71         #
72         # Entry.objects.filter(pub_date__day=3)
73         # Entry.objects.filter(pub_date__day__gte=3)
74 
75         # week_day
76         #
77         # Entry.objects.filter(pub_date__week_day=2)
78         # Entry.objects.filter(pub_date__week_day__gte=2)
79 
80         # hour
81         #
82         # Event.objects.filter(timestamp__hour=23)
83         # Event.objects.filter(time__hour=5)
84         # Event.objects.filter(timestamp__hour__gte=12)
85 
86         # minute
87         #
88         # Event.objects.filter(timestamp__minute=29)
89         # Event.objects.filter(time__minute=46)
90         # Event.objects.filter(timestamp__minute__gte=29)
91 
92         # second
93         #
94         # Event.objects.filter(timestamp__second=31)
95         # Event.objects.filter(time__second=2)
96         # Event.objects.filter(timestamp__second__gte=31)
操作---进阶
技术分享
 1 # extra    #额外查询条件以及相关表,排序
 2         #
 3         # extra(self, select=None, where=None, params=None, tables=None, order_by=None, select_params=None)
 4     # a. 映射
 5         # select 
 6         # select_params=None
 7         # select 此处 from 表
 8                 
 9     # b. 条件
10         # where=None
11         # params=None,
12         # select * from 表 where 此处
13                 
14     # c. 表
15         # tables
16         # select * from 表,此处
17                     
18     # c. 排序
19         # order_by=None
20         # select * from 表 order by 此处
21 
22         #    Entry.objects.extra(select={‘new_id‘: "select col from sometable where othercol > %s"}, select_params=(1,))
23         #    Entry.objects.extra(where=[‘headline=%s‘], params=[‘Lennon‘])
24         #    Entry.objects.extra(where=["foo=‘a‘ OR bar = ‘a‘", "baz = ‘a‘"])
25         #    Entry.objects.extra(select={‘new_id‘: "select id from tb where id > %s"}, select_params=(1,), order_by=[‘-nid‘])
26 
27         # F   #更新时用于获取原来的值
28         
29          from django.db.models import F
30          models.Tb1.objects.update(num=F(num)+1)
31 
32 
33         # Q   #用于构造复杂查询条件
34         
35     # 应用一:
36         models.UserInfo.objects.filter(Q(id__gt=1))
37         models.UserInfo.objects.filter(Q(id=8) | Q(id=2))
38         models.UserInfo.objects.filter(Q(id=8) & Q(id=2))
39 
40         # 应用二:
41         # con = Q()
42         # q1 = Q()
43         # q1.connector = ‘OR‘
44         # q1.children.append((‘id‘, 1))
45         # q1.children.append((‘id‘, 10))
46         # q1.children.append((‘id‘, 9))
47         # q2 = Q()
48         # q2.connector = ‘OR‘
49         # q2.children.append((‘c1‘, 1))
50         # q2.children.append((‘c1‘, 10))
51         # q2.children.append((‘c1‘, 9))
52         # con.add(q1, ‘AND‘)
53         # con.add(q2, ‘AND‘)
54         #
55         # models.Tb1.objects.filter(con)
56 
57 
58         # 执行原生SQL
59         #
60         # from django.db import connection, connections
61         # cursor = connection.cursor()  # cursor = connections[‘default‘].cursor()
62         # cursor.execute("""SELECT * from auth_user where id = %s""", [1])
63         # row = cursor.fetchone()
操级---高级
技术分享
  1 ##################################################################
  2 # PUBLIC METHODS THAT ALTER ATTRIBUTES AND RETURN A NEW QUERYSET #
  3 ##################################################################
  4 
  5 def all(self)
  6     # 获取所有的数据对象
  7 
  8 def filter(self, *args, **kwargs)
  9     # 条件查询
 10     # 条件可以是:参数,字典,Q
 11 
 12 def exclude(self, *args, **kwargs)
 13     # 条件查询
 14     # 条件可以是:参数,字典,Q
 15 
 16 def select_related(self, *fields)
 17      性能相关:表之间进行join连表操作,一次性获取关联的数据。
 18      model.tb.objects.all().select_related()
 19      model.tb.objects.all().select_related(外键字段)
 20      model.tb.objects.all().select_related(外键字段__外键字段)
 21 
 22 def prefetch_related(self, *lookups)
 23     性能相关:多表连表操作时速度会慢,使用其执行多次SQL查询在Python代码中实现连表操作。
 24             # 获取所有用户表
 25             # 获取用户类型表where id in (用户表中的查到的所有用户ID)
 26             models.UserInfo.objects.prefetch_related(外键字段)
 27 
 28 
 29 
 30             from django.db.models import Count, Case, When, IntegerField
 31             Article.objects.annotate(
 32                 numviews=Count(Case(
 33                     When(readership__what_time__lt=treshold, then=1),
 34                     output_field=CharField(),
 35                 ))
 36             )
 37 
 38             students = Student.objects.all().annotate(num_excused_absences=models.Sum(
 39                 models.Case(
 40                     models.When(absence__type=Excused, then=1),
 41                 default=0,
 42                 output_field=models.IntegerField()
 43             )))
 44 
 45 def annotate(self, *args, **kwargs)
 46     # 用于实现聚合group by查询
 47 
 48     from django.db.models import Count, Avg, Max, Min, Sum
 49 
 50     v = models.UserInfo.objects.values(u_id).annotate(uid=Count(u_id))
 51     # SELECT u_id, COUNT(ui) AS `uid` FROM UserInfo GROUP BY u_id
 52 
 53     v = models.UserInfo.objects.values(u_id).annotate(uid=Count(u_id)).filter(uid__gt=1)
 54     # SELECT u_id, COUNT(ui_id) AS `uid` FROM UserInfo GROUP BY u_id having count(u_id) > 1
 55 
 56     v = models.UserInfo.objects.values(u_id).annotate(uid=Count(u_id,distinct=True)).filter(uid__gt=1)
 57     # SELECT u_id, COUNT( DISTINCT ui_id) AS `uid` FROM UserInfo GROUP BY u_id having count(u_id) > 1
 58 
 59 def distinct(self, *field_names)
 60     # 用于distinct去重
 61     models.UserInfo.objects.values(nid).distinct()
 62     # select distinct nid from userinfo
 63 
 64     注:只有在PostgreSQL中才能使用distinct进行去重
 65 
 66 def order_by(self, *field_names)
 67     # 用于排序
 68     models.UserInfo.objects.all().order_by(-id,age)
 69 
 70 def extra(self, select=None, where=None, params=None, tables=None, order_by=None, select_params=None)
 71     # 构造额外的查询条件或者映射,如:子查询
 72 
 73     Entry.objects.extra(select={new_id: "select col from sometable where othercol > %s"}, select_params=(1,))
 74     Entry.objects.extra(where=[headline=%s], params=[Lennon])
 75     Entry.objects.extra(where=["foo=‘a‘ OR bar = ‘a‘", "baz = ‘a‘"])
 76     Entry.objects.extra(select={new_id: "select id from tb where id > %s"}, select_params=(1,), order_by=[-nid])
 77 
 78  def reverse(self):
 79     # 倒序
 80     models.UserInfo.objects.all().order_by(-nid).reverse()
 81     # 注:如果存在order_by,reverse则是倒序,如果多个排序则一一倒序
 82 
 83 
 84  def defer(self, *fields):
 85     models.UserInfo.objects.defer(username,id)
 86  87     models.UserInfo.objects.filter(...).defer(username,id)
 88     #映射中排除某列数据
 89 
 90  def only(self, *fields):
 91     #仅取某个表中的数据
 92      models.UserInfo.objects.only(username,id)
 93  94      models.UserInfo.objects.filter(...).only(username,id)
 95 
 96  def using(self, alias):
 97      指定使用的数据库,参数为别名(setting中的设置)
 98 
 99 
100 ##################################################
101 # PUBLIC METHODS THAT RETURN A QUERYSET SUBCLASS #
102 ##################################################
103 
104 def raw(self, raw_query, params=None, translations=None, using=None):
105     # 执行原生SQL
106     models.UserInfo.objects.raw(select * from userinfo)
107 
108     # 如果SQL是其他表时,必须将名字设置为当前UserInfo对象的主键列名
109     models.UserInfo.objects.raw(select id as nid from 其他表)
110 
111     # 为原生SQL设置参数
112     models.UserInfo.objects.raw(select id as nid from userinfo where nid>%s, params=[12,])
113 
114     # 将获取的到列名转换为指定列名
115     name_map = {first: first_name, last: last_name, bd: birth_date, pk: id}
116     Person.objects.raw(SELECT * FROM some_other_table, translations=name_map)
117 
118     # 指定数据库
119     models.UserInfo.objects.raw(select * from userinfo, using="default")
120 
121     ################### 原生SQL ###################
122     from django.db import connection, connections
123     cursor = connection.cursor()  # cursor = connections[‘default‘].cursor()
124     cursor.execute("""SELECT * from auth_user where id = %s""", [1])
125     row = cursor.fetchone() # fetchall()/fetchmany(..)
126 
127 
128 def values(self, *fields):
129     # 获取每行数据为字典格式
130 
131 def values_list(self, *fields, **kwargs):
132     # 获取每行数据为元祖
133 
134 def dates(self, field_name, kind, order=ASC):
135     # 根据时间进行某一部分进行去重查找并截取指定内容
136     # kind只能是:"year"(年), "month"(年-月), "day"(年-月-日)
137     # order只能是:"ASC"  "DESC"
138     # 并获取转换后的时间
139         - year : 年-01-01
140         - month: 年-月-01
141         - day  : 年-月-142 
143     models.DatePlus.objects.dates(ctime,day,DESC)
144 
145 def datetimes(self, field_name, kind, order=ASC, tzinfo=None):
146     # 根据时间进行某一部分进行去重查找并截取指定内容,将时间转换为指定时区时间
147     # kind只能是 "year", "month", "day", "hour", "minute", "second"
148     # order只能是:"ASC"  "DESC"
149     # tzinfo时区对象
150     models.DDD.objects.datetimes(ctime,hour,tzinfo=pytz.UTC)
151     models.DDD.objects.datetimes(ctime,hour,tzinfo=pytz.timezone(Asia/Shanghai))
152 
153     """
154     pip3 install pytz
155     import pytz
156     pytz.all_timezones
157     pytz.timezone(‘Asia/Shanghai’)
158     """
159 
160 def none(self):
161     # 空QuerySet对象
162 
163 
164 ####################################
165 # METHODS THAT DO DATABASE QUERIES #
166 ####################################
167 
168 def aggregate(self, *args, **kwargs):
169    # 聚合函数,获取字典类型聚合结果
170    from django.db.models import Count, Avg, Max, Min, Sum
171    result = models.UserInfo.objects.aggregate(k=Count(u_id, distinct=True), n=Count(nid))
172    ===> {k: 3, n: 4}
173 
174 def count(self):
175    # 获取个数
176 
177 def get(self, *args, **kwargs):
178    # 获取单个对象
179 
180 def create(self, **kwargs):
181    # 创建对象
182 
183 def bulk_create(self, objs, batch_size=None):
184     # 批量插入
185     # batch_size表示一次插入的个数
186     objs = [
187         models.DDD(name=r11),
188         models.DDD(name=r22)
189     ]
190     models.DDD.objects.bulk_create(objs, 10)
191 
192 def get_or_create(self, defaults=None, **kwargs):
193     # 如果存在,则获取,否则,创建
194     # defaults 指定创建时,其他字段的值
195     obj, created = models.UserInfo.objects.get_or_create(username=root1, defaults={email: 1111111,u_id: 2, t_id: 2})
196 
197 def update_or_create(self, defaults=None, **kwargs):
198     # 如果存在,则更新,否则,创建
199     # defaults 指定创建时或更新时的其他字段
200     obj, created = models.UserInfo.objects.update_or_create(username=root1, defaults={email: 1111111,u_id: 2, t_id: 1})
201 
202 def first(self):
203    # 获取第一个
204 
205 def last(self):
206    # 获取最后一个
207 
208 def in_bulk(self, id_list=None):
209    # 根据主键ID进行查找
210    id_list = [11,21,31]
211    models.DDD.objects.in_bulk(id_list)
212 
213 def delete(self):
214    # 删除
215 
216 def update(self, **kwargs):
217     # 更新
218 
219 def exists(self):
220    # 是否有结果
221 
222 其他操作
其他操作

十三、多表关系以及参数 

技术分享
  1 ForeignKey(ForeignObject) # ForeignObject(RelatedField)
  2         to,                         # 要进行关联的表名
  3         to_field=None,              # 要关联的表中的字段名称
  4         on_delete=None,             # 当删除关联表中的数据时,当前表与其关联的行的行为
  5                                         - models.CASCADE,删除关联数据,与之关联也删除
  6                                         - models.DO_NOTHING,删除关联数据,引发错误IntegrityError
  7                                         - models.PROTECT,删除关联数据,引发错误ProtectedError
  8                                         - models.SET_NULL,删除关联数据,与之关联的值设置为null(前提FK字段需要设置为可空)
  9                                         - models.SET_DEFAULT,删除关联数据,与之关联的值设置为默认值(前提FK字段需要设置默认值)
 10                                         - models.SET,删除关联数据,
 11                                                       a. 与之关联的值设置为指定值,设置:models.SET(值)
 12                                                       b. 与之关联的值设置为可执行对象的返回值,设置:models.SET(可执行对象)
 13 
 14                                                         def func():
 15                                                             return 10
 16 
 17                                                         class MyModel(models.Model):
 18                                                             user = models.ForeignKey(
 19                                                                 to="User",
 20                                                                 to_field="id"
 21                                                                 on_delete=models.SET(func),)
 22         related_name=None,          # 反向操作时,使用的字段名,用于代替 【表名_set】 如: obj.表名_set.all()
 23         related_query_name=None,    # 反向操作时,使用的连接前缀,用于替换【表名】     如: models.UserGroup.objects.filter(表名__字段名=1).values(‘表名__字段名‘)
 24         limit_choices_to=None,      # 在Admin或ModelForm中显示关联数据时,提供的条件:
 25                                     # 如:
 26                                             - limit_choices_to={nid__gt: 5}
 27                                             - limit_choices_to=lambda : {nid__gt: 5}
 28 
 29                                             from django.db.models import Q
 30                                             - limit_choices_to=Q(nid__gt=10)
 31                                             - limit_choices_to=Q(nid=8) | Q(nid__gt=10)
 32                                             - limit_choices_to=lambda : Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption=root)
 33         db_constraint=True          # 是否在数据库中创建外键约束
 34         parent_link=False           # 在Admin中是否显示关联数据
 35 
 36 
 37     OneToOneField(ForeignKey)
 38         to,                         # 要进行关联的表名
 39         to_field=None               # 要关联的表中的字段名称
 40         on_delete=None,             # 当删除关联表中的数据时,当前表与其关联的行的行为
 41 
 42                                     ###### 对于一对一 ######
 43                                     # 1. 一对一其实就是 一对多 + 唯一索引
 44                                     # 2.当两个类之间有继承关系时,默认会创建一个一对一字段
 45                                     # 如下会在A表中额外增加一个c_ptr_id列且唯一:
 46                                             class C(models.Model):
 47                                                 nid = models.AutoField(primary_key=True)
 48                                                 part = models.CharField(max_length=12)
 49 
 50                                             class A(C):
 51                                                 id = models.AutoField(primary_key=True)
 52                                                 code = models.CharField(max_length=1)
 53 
 54     ManyToManyField(RelatedField)
 55         to,                         # 要进行关联的表名
 56         related_name=None,          # 反向操作时,使用的字段名,用于代替 【表名_set】 如: obj.表名_set.all()
 57         related_query_name=None,    # 反向操作时,使用的连接前缀,用于替换【表名】     如: models.UserGroup.objects.filter(表名__字段名=1).values(‘表名__字段名‘)
 58         limit_choices_to=None,      # 在Admin或ModelForm中显示关联数据时,提供的条件:
 59                                     # 如:
 60                                             - limit_choices_to={nid__gt: 5}
 61                                             - limit_choices_to=lambda : {nid__gt: 5}
 62 
 63                                             from django.db.models import Q
 64                                             - limit_choices_to=Q(nid__gt=10)
 65                                             - limit_choices_to=Q(nid=8) | Q(nid__gt=10)
 66                                             - limit_choices_to=lambda : Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption=root)
 67         symmetrical=None,           # 仅用于多对多自关联时,symmetrical用于指定内部是否创建反向操作的字段
 68                                     # 做如下操作时,不同的symmetrical会有不同的可选字段
 69                                         models.BB.objects.filter(...)
 70 
 71                                         # 可选字段有:code, id, m1
 72                                             class BB(models.Model):
 73 
 74                                             code = models.CharField(max_length=12)
 75                                             m1 = models.ManyToManyField(self,symmetrical=True)
 76 
 77                                         # 可选字段有: bb, code, id, m1
 78                                             class BB(models.Model):
 79 
 80                                             code = models.CharField(max_length=12)
 81                                             m1 = models.ManyToManyField(self,symmetrical=False)
 82 
 83         through=None,               # 自定义第三张表时,使用字段用于指定关系表
 84         through_fields=None,        # 自定义第三张表时,使用字段用于指定关系表中那些字段做多对多关系表
 85                                         from django.db import models
 86 
 87                                         class Person(models.Model):
 88                                             name = models.CharField(max_length=50)
 89 
 90                                         class Group(models.Model):
 91                                             name = models.CharField(max_length=128)
 92                                             members = models.ManyToManyField(
 93                                                 Person,
 94                                                 through=Membership,
 95                                                 through_fields=(group, person),
 96                                             )
 97 
 98                                         class Membership(models.Model):
 99                                             group = models.ForeignKey(Group, on_delete=models.CASCADE)
100                                             person = models.ForeignKey(Person, on_delete=models.CASCADE)
101                                             inviter = models.ForeignKey(
102                                                 Person,
103                                                 on_delete=models.CASCADE,
104                                                 related_name="membership_invites",
105                                             )
106                                             invite_reason = models.CharField(max_length=64)
107         db_constraint=True,         # 是否在数据库中创建外键约束
108         db_table=None,                # 默认创建第三张表时,数据库中表的名称
多表关系以及参数

 

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