Django（二）

一、路由系统，URL
    1、url(r'^index/', views.index),   
         url(r'^home/', views.Home.as_view()),
    2、url(r'^detail-(\d+).html', views.detail), url(r'^detail-(\d+)-(\d+)', views.detail),
    3、url(r'^detail-(?P<nid>\d+)-(?P<uid>\d+).html', views.detail)

       PS:
            def detail(request, *args,**kwargs):
                pass

       实战：
            a.
                url(r'^detail-(\d+)-(\d+).html', views.detail),

                def func(request, nid, uid):

                    pass

                def func(request, *args):
                    args = (2,9)

                def func(request, *args, **kwargs):
                    args = (2,9)

            b.
                url(r'^detail-(?P<nid>\d+)-(?P<uid>\d+).html', views.detail)

                def func(request, nid, uid):
                    pass

                def funct(request, **kwargs):
                    kwargs = {'nid': 1, 'uid': 3}

                def func(request, *args, **kwargs):
                    args = (2,9)
    4、 name

        对URL路由关系进行命名， ***** 以后可以根据此名称生成自己想要的URL *****

        url(r'^asdfasdfasdf/', views.index, name='i1'),
        url(r'^yug/(\d+)/(\d+)/', views.index, name='i2'),
        url(r'^buy/(?P<pid>\d+)/(?P<nid>\d+)/', views.index, name='i3'),

        def func(request, *args, **kwargs):
            from django.urls import reverse

            url1 = reverse('i1')                              # asdfasdfasdf/
            url2 = reverse('i2', args=(1,2,))                 # yug/1/2/
            url3 = reverse('i3', kwargs={'pid': 1, "nid": 9}) # buy/1/9/

        xxx.html

            {% url "i1" %}               # asdfasdfasdf/
            {% url "i2" 1 2 %}           # yug/1/2/
            {% url "i3" pid=1 nid=9 %}   # buy/1/9/

        注：
            # 当前的URL
            request.path_info
    5、多级路由

        project/urls.py
            from django.conf.urls import url,include
            from django.contrib import admin

            urlpatterns = [
                url(r'^cmdb/', include("app01.urls")),
                url(r'^monitor/', include("app02.urls")),
            ]

        app01/urls.py
            from django.conf.urls import url,include
            from django.contrib import admin
            from app01 import views

            urlpatterns = [
                url(r'^login/', views.login),
            ]

        app02/urls.py
            from django.conf.urls import url,include
            from django.contrib import admin
            from app02 import views

            urlpatterns = [
                url(r'^login/', views.login),
            ]

二、视图
    1、获取用户请求数据
        request.GET
        request.POST
        request.FILES
        PS:
            GET:获取数据               
            POST:提交数据

    2、checkbox等多选的内容
        request.POST.getlist()
    3、上传文件
        # 上传文件,form标签做特殊设置(enctype="multipart/form-data")
        obj = request.FILES.get('fafafa')
        obj.name
        f = open(obj.name, mode='wb')
        for item in obj.chunks():
            f.write(item)
        f.close()

    4、FBV & CBV
       function base view
       class base view

        url.py
            index -> 函数名

        view.py
            def 函数(request):
                ...
        ====》
        /index/ -> 函数名

        /index/ -> 类

        ====》

        建议：两者都用

三、模板

四、ORM操作
    select * from tb where id > 1
    # 对应关系
    models.tb.objects.filter(id__gt=1)
    models.tb.objects.filter(id=1)
    models.tb.objects.filter(id__lt=1)

    创建类

    a. 先写类
        from django.db import models

        # app01_userinfo
        class UserInfo(models.Model):
            # id列，自增，主键
            # 用户名列，字符串类型，指定长度
            username = models.CharField(max_length=32)
            password = models.CharField(max_length=64)

    b. 注册APP

        INSTALLED_APPS = [
            'django.contrib.admin',
            'django.contrib.auth',
            'django.contrib.contenttypes',
            'django.contrib.sessions',
            'django.contrib.messages',
            'django.contrib.staticfiles',
            'app01',
        ]
    c. 执行命令
        python manage.py  makemigrations
        python manage.py  migrate

    d. ********** 注意 ***********
　　mysql数据库
　　DATABASES = {
   　　 'default': {
   　　 'ENGINE': 'django.db.backends.mysql',
   　　 'NAME':'dbname',
   　　 'USER': 'root',
   　　 'PASSWORD': 'xxx',
   　　 'HOST': '',
    　　'PORT': '',
   　　 }

　　}
        Django默认使用MySQLdb模块链接MySQL
        主动修改为pymysql，在project同名文件夹下的__init__文件中添加如下代码即可：
            import pymysql
            pymysql.install_as_MySQLdb()

    1. 根据类自动创建数据库表
        # app下的models.py

        python manage.py  makemigrations
        python manage.py  migrate

        字段：
            字符串类型
            数字
            时间
            二进制
            自增（primary_key=True）

        字段的参数：
            null               -> db是否可以为空
            default            -> 默认值
            primary_key        -> 主键
            db_column          -> 列名
            db_index           -> 索引
            unique               -> 唯一索引
            unique_for_date    ->
            unique_for_month
            unique_for_year
            auto_now           -> 创建时，自动生成时间
            auto_now_add       -> 更新时，自动更新为当前时间

                # obj = UserGroup.objects.filter(id=1).update(caption='CEO')
                # obj = UserGroup.objects.filter(id=1).first()
                # obj.caption = "CEO"
                # obj.save()

            choices              -> django admin中显示下拉框，避免连表查询
            blank             -> django admin是否可以为空
            verbose_name      -> django admin显示字段中文
            editable          -> django admin是否可以被编辑
            error_messages    -> 错误信息欠
            help_text         -> django admin提示
            validators          -> django form ,自定义错误信息（欠）

            创建 Django 用户：python manage.py createsuperuser

          数据库的基本操作：
          from app01 import models
  　　  def orm(request):
    
   
              a.创建
               models.UserInfo.objects.create(username = "root",password = '123')
               return HttpResponse('orm')
             b.删
       　　　models.UserInfo.objects.filter(username='eric').delete()
      　　　 return HttpResponse(orm)
      　　 c.改
　　　　　models.UserInfo.objects.all().update(password='111')
　　　　　models.UserInfo.objects.filter(id=2).update(password='555')
        　　return HttpResponse(orm)

           d.查
    　　　　result = models.UserInfo.objects.all() --->查全部
   　　　　 result = models.UserInfo.objects.filter(username='root')  --->查name是root的
   　　　　 for row in result:
      　　　　  print(row.id,row.username,row.password)
   　　　　 print(result)
   　　　　 return HttpResponse(orm)

             

    2. 根据类对数据库表中的数据进行各种操作

        一对多：

            a. 外检
            b.
                外键字段_id
            c.
                models.tb.object.create(name='root', user_group_id=1)

            d.

                userlist = models.tb.object.all()
                for row in userlist:
                    row.id
                    row.user_group_id
                    row.user_group.caption