python篇：Django框架基本增删改查

人生苦短，我要学python！

 python也有框架，那就是Django，它是集成框架，这个框架可以执行所有的操作，不像SSM是由三个框架组成的。

首先，是在pycharm中新建Django项目。

注意：在新建时，目录下还有操作。

打开树形选项，写入项目的版块名，目的是为了插件式开发，各版块共同存在且互不影响，却又组成了一个大项目。

新建欧克后，有两个文件是自动打开的。

Django项目分为了三个文件夹。

第一个大文件夹是：Django项目的基本配置，它与Django项目同名

它的

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__init__.py很重要！

# alt+enter回车
import pymysql
pymysql.install_as_MySQLdb()

这是pymysql的导包，即数据库连接包的配置。

接下来，是settings.py

"""
Django settings for DjangoWeb project.

Generated by 'django-admin startproject' using Django 2.1.2.

For more information on this file, see
https://docs.djangoproject.com/en/2.1/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/2.1/ref/settings/
"""

import os

# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/2.1/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'x5onoylzr5*th%mp&qolaaw$qa_$6!_1k$*!#9z-vsvv)y_5l_'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []

# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'Student.apps.StudentConfig',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'DjangoWeb.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')]
        ,
        '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',
            ],
        },
    },
]

WSGI_APPLICATION = 'DjangoWeb.wsgi.application'

# Database
# https://docs.djangoproject.com/en/2.1/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        # 'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
        'NAME': 'cn',
        'USER': 'root',
        'PASSWORD': 'root',
        'HOST': '127.0.0.1'
    }
}

# Password validation
# https://docs.djangoproject.com/en/2.1/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

# Internationalization
# https://docs.djangoproject.com/en/2.1/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/2.1/howto/static-files/

STATIC_URL = '/static/'

只需要注意databases
DATABASES是数据库配置信息

将它改为自己的格式，engine 改为你需要的数据库种类，其他的如：数据库名、用户、密码、连接地址。

接下来是urls.py

"""DjangoWeb URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path

from Student import views

urlpatterns = [
    path('admin/', admin.site.urls),
    # path('') http://127.0.0.1:8000/
    path('', views.first),
    path('first.html', views.first),
    path('insert.html', views.insert),
    path('insertUser.html', views.insertUser),
path('delete.html', views.delete),
path('update.html', views.update),
path('updateUser.html', views.updateUser),
]

先导入第二个大文件夹即所建的板块的views

urlpatterns：是路径

系统自动配置了一个admin的路径，这是后台会用到的。

path（‘’）：为默认路径，项目一运行就会进入，调用views中的方法，注意方法后面不带括号。

第二个大文件夹，即所建的板块。

这里，

# This is an auto-generated Django model module.
# You'll have to do the following manually to clean this up:
#   * Rearrange models' order
#   * Make sure each model has one field with primary_key=True
#   * Make sure each ForeignKey has `on_delete` set to the desired behavior.
#   * Remove `managed = False` lines if you wish to allow Django to create, modify, and delete the table
# Feel free to rename the models, but don't rename db_table values or field names.
from django.db import models


# python manage.py inspectdb > student/models.py

class User(models.Model):
    userid = models.AutoField(db_column='userId', primary_key=True)  # Field name made lowercase.
    username = models.CharField(db_column='userName', max_length=255, blank=True,
                                null=True)  # Field name made lowercase.
    usersay = models.CharField(db_column='userSay', max_length=255, blank=True, null=True)  # Field name made lowercase.

    class Meta:
        managed = False
        db_table = 'user'

这是对象的储存地。

配置好数据库连接后，在terminal控制台输入

python manage.py inspectdb > student/models.py

即可从MySQL中将表导入为对象，对象的属性名以models中的为准。

接下来：

from django.shortcuts import render
from django.shortcuts import HttpResponse
from django.shortcuts import redirect
from Student.models import *


# Create your views here.


def first(request):
    users=User.objects.all()
    count = users.__len__()
    return render(request, 'first.html', context={'users': users, 'count': count})

# {% csrf_token %} Forbidden (403)

def delete(request):
    uid=request.GET.get('uid')
    User.objects.filter(userid=uid).delete()#找到则删除
    return redirect('first.html')

def update(request):
    uid = request.GET.get('uid')
    user=User.objects.get(userid=uid)
    return render(request,'update.html',context={'user':user})

def updateUser(request):
    userId = request.POST.get('userId')
    userName = request.POST.get('userName')
    userSay = request.POST.get('userSay')
    User.objects.filter(userid=userId).update(username=userName, usersay=userSay)
    return redirect('first.html')

def insert(request):
    return render(request, 'insert.html')


def insertUser(request):
    userName = request.POST.get('userName')
    userSay = request.POST.get('userSay')
    User.objects.create(username=userName, usersay=userSay)
    return redirect('first.html')#重定向

# def insert(request):
#     if request.method=='POST':
#         userName=request.POST.get('userName')
#         userSay=request.POST.get('userSay')
#         User.objects.create(username=userName,usersay=userSay)
#         return redirect('first.html')
#     else:
#         return render(request, 'insert.html')

这是views，urls匹配到正确的路径后，会调用这里的方法。

调用数据，对象

.objects

然后，调用具体操作方法。

all：表中所有数据

第三个大文件夹，是HTML页面。

first：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>hello world</title>
</head>
<body>
用户管理
总数：{{ count }}
<a href="insert.html">新增用户</a>

<div align="center">

<table border="1">

    <thead>
    <th>编号</th>
    <th>姓名</th>
    <th>言论</th>
    <th>删除</th>
    <th>修改</th>
    </thead>
    <tbody>
    {% for user in users %}
        <tr>
            <td>{{ user.userid }}</td>
            <td>{{ user.username }}</td>
            <td>{{ user.usersay }}</td>
            <td><a href="delete.html?uid={{ user.userid }}">删除</a></td>
        <td><a href="update.html?uid={{ user.userid }}">修改</a></td>
        </tr>
    {% endfor %}

    </tbody>

</table>
</div>
</body>
</html>

insert：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>insert</title>
</head>
<body>
<div align="center">
    <form action="insertUser.html" method="post">
        {% csrf_token %}
        姓名：<input type="text" name="userName"><br>
        言论：<input type="text" name="userSay"><br>
        <input type="submit" value="添加">
    </form>
</div>
</body>
</html>

提交表单数据，必须

{% csrf_token %}

update：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>update</title>
</head>
<body>
<div align="center">
    <form action="updateUser.html" method="post">
        {% csrf_token %}
        <input type="hidden" name="userId" value="{{ user.userid }}">
        姓名：<input type="text" name="userName" value="{{user.username  }}"><br>
        言论：<input type="text" name="userSay" value="{{user.usersay }}"><br>
        <input type="submit" value="添加">
    </form>
</div>
</body>
</html>

非常好用！

期待python的爬虫！