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梅科尔工作室-DjangoWeb 应用框架+MySQL数据库第三次培训

2022-08-11 05:23:00 C_yyy89

前言

本文是记录DjangoWeb 应用框架+MySQL数据库第三次培训的笔记,包含

Django小白入门到实战教程(2021)_哔哩哔哩_bilibili

P6-P11的学习笔记,以及Django的ORM学习笔记

感谢梅姐的教学!


1.DJango路由

路由简单的来说就是根据用户请求的 URL 链接来判断对应的处理程序,并返回处理结果,也就是 URL 与 Django 的视图建立映射关系。

Django 路由在 urls.py 配置,urls.py 中的每一条配置对应相应的处理方法。

1.1配置urls路由

首先,在djangoProject文件夹下新建一个app,命名为student,启动终端,在C:\Users\11252\Desktop\djangoProject路径下输入如下代码即可。

python manage.py startapp student

4ff4e83881d5495ab76fa1908e65a160.png

如上图,app创建完成。

下一步,修改settings.py文件。

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'student', #新增student
]

修改djangoProject文件夹下的urls.py文件。

from django.contrib import admin
from django.urls import path, include #新增include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('student.urls')), #新增student路径
]

 修改student文件下的urls.py文件,复制上方代码,再修改即可。

from django.urls import path

urlpatterns = [
    
]

 2.展示HTML页面

启动Django服务时,将展示出home页面。

编写student文件下的urls.py文件,准备展示home页面

from django.urls import path
from . import views
urlpatterns = [
    path('', views.home, name="home")
]

 在student文件下新建templates文件夹,在templates文件夹下创建home.html文件,并编写Hello World!

4da0700f02644f02af836a9b0396f5c4.png

<h1>Hello World!</h1>

 编写views.py,新增home方法

from django.shortcuts import render

# Create your views here.
def home(request):
    return render(request, 'home.html', {})

启动django服务

python manage.py runserver 127.0.0.1:8000 

效果如下: 

891974c27d5843e896ba3eea15b94a44.png

3.创建公共HTML模板

使用bootstrap框架美化页面,要用到Bootstrap4的入门模板,链接如下:

简介 · Bootstrap v4 中文文档 v4.6 | Bootstrap 中文网 (bootcss.com)

复制入门模板代码

<!doctype html>
<html lang="zh-CN">
  <head>
    <!-- 必须的 meta 标签 -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap 的 CSS 文件 -->
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" integrity="sha384-p1KAotb3W9ndluCsqePPYnjRm3c6abdnIjo0tQwYUv83VsbsYd43RuofnFAaDo0E" crossorigin="anonymous">

    <title>Hello, world!</title>
  </head>
  <body>
    <h1>Hello, world!</h1>

    <!-- JavaScript 文件是可选的。从以下两种建议中选择一个即可! -->

    <!-- 选项 1:jQuery 和 Bootstrap 集成包(集成了 Popper) -->
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-E5Sj1saJVFNzWWK3YIJB4LEDEEVEGaOdfmCprPDkfWUo+xkb6Ep52Q1TMEtgcFwi" crossorigin="anonymous"></script>

    <!-- 选项 2:Popper 和 Bootstrap 的 JS 插件各自独立 -->
    <!--
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/umd/popper.min.js" integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.min.js" integrity="sha384-IjeXbuVdL81ilB5LykkImU8JN0WPja/i9uZAt2qjo2TnYk9NJ2MPfN3vzMH0R8n3" crossorigin="anonymous"></script>
    -->
  </body>
</html>

在templates文件夹下创建base.html文件,并将上方代码粘贴到此文件中,修改home.html文件,代码如下:

{% extends 'base.html' %}
{% block content %}
    <h1>Hello World!</h1>
    <p>测试是否可以看到我</p>
{% endblock %}

在base.html文件中调用home.html并写入导航link

<!doctype html>
<html lang="zh-CN">
  <head>
    <!-- 必须的 meta 标签 -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap 的 CSS 文件 -->
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" integrity="sha384-p1KAotb3W9ndluCsqePPYnjRm3c6abdnIjo0tQwYUv83VsbsYd43RuofnFAaDo0E" crossorigin="anonymous">

    <title>Hello, world!</title>
  </head>
#在这里!!!
  <body>
    link1 || link2 || link3
    {% block content %}
    {% endblock %}
#在这里!!!
    <!-- JavaScript 文件是可选的。从以下两种建议中选择一个即可! -->

    <!-- 选项 1:jQuery 和 Bootstrap 集成包(集成了 Popper) -->
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-E5Sj1saJVFNzWWK3YIJB4LEDEEVEGaOdfmCprPDkfWUo+xkb6Ep52Q1TMEtgcFwi" crossorigin="anonymous"></script>

    <!-- 选项 2:Popper 和 Bootstrap 的 JS 插件各自独立 -->
    <!--
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/umd/popper.min.js" integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.min.js" integrity="sha384-IjeXbuVdL81ilB5LykkImU8JN0WPja/i9uZAt2qjo2TnYk9NJ2MPfN3vzMH0R8n3" crossorigin="anonymous"></script>
    -->
  </body>
</html>

效果如下:7c46a484309e4c149ad6b1eaa754133f.png 

 4.展示导航信息

导航条代码来源Navbar · Bootstrap v4 中文文档 v4.6 | Bootstrap 中文网 (bootcss.com)

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-expanded="false">
          Dropdown
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled">Disabled</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>

效果如下:遇到了未知bug,效果和预期不同!!!(bug已修复,link标签加载css资源失败是因为哈希校验不通过,把integrity和crossorigin属性删除即可

56544209c3bc437294ef395a8e75c9e3.png 5.接口请求和解析 

接口地址:https://api.github.com/users?since=0

准备工作:在终端输入pip install requests,安装requests插件。

在views.py文件里做以下修改,导入接口,最后return将获取的数据放入home页面

from django.shortcuts import render

# Create your views here.
def home(request):
    import requests
    import json
    api_request = requests.get("https://api.github.com/users?since=0")
    api = json.loads(api_request.content)
    return render(request, 'home.html', {"api":api})

 在home.html文件里做以下修改,将获取的数据放入home页面

{% extends 'base.html' %}
{% block content %}
    <h1>Hello World!</h1>
    <p>{
   { api }}</p>
{% endblock %}

 效果如下,可以看到导航条已经恢复了:

6.DJango ORM实现增、删、改、查 

6.1准备工作

先建表,并重新展示页面,这里以学生管理表为例

在models.py文件中写入如下代码:

from django.db import models

# Create your models here.
class Students(models.Model):
    Name=models.CharField(max_length=12)
    Email=models.IntegerField(max_length=20)
    Age=models.IntegerField(max_length=12)

djangoProject路径下的urls文件做出修改,新增student_list页面路径

from django.contrib import admin
from django.urls import path, include
from student import views
urlpatterns = [
    path('admin/', admin.site.urls),
    path('three', include('student.urls')),
    path('student_list', views.student_list),
]

在views.py中新增代码

def student_list(request):
    student_queryset = models.Students.objects.all()
    # person1 = models.Students.objects.create(Name="如来", Email=200000, Age=8888)
    # print(person1, type(person1))
    return render(request, "student.html", {"student_queryset": student_queryset})

编写student.html文件 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>学生管理</title>
</head>
<body>
<table border="1">
    <thead>
    <tr>
        <td>id</td>
        <td>姓名</td>
        <td>邮箱</td>
        <td>年龄</td>
    </tr>
    </thead>
    <tbody>
    {% for student in student_queryset %}
        <tr>
            <td>{
   { student.id }}</td>
            <td>{
   { student.Name }}</td>
            <td>{
   { student.Email }}</td>
            <td>{
   { student.Age }}</td>
        </tr>
    {% endfor %}


    </tbody>
</table>
</body>
</html>

迁移表格,执行迁移

python manage.py makemigrations
 
python manage.py migrate

在student_students数据库中手动写入数据 

def student_list(request):
    student_queryset = models.Students.objects.all()
    person1 = models.Students.objects.create(Name="如来", Email=200000, Age=8888)
    print(person1, type(person1))
    return render(request, "student.html", {"student_queryset": student_queryset})

访问新页面,如图,准备工作完成 

 6.2 增的实现

UserInfo.objects.create(username='root',passwd='123456')

在views.py下的student_list方法中增加orm的增操作,如下

def student_list(request):
    student_queryset = models.Students.objects.all()
    person1 = models.Students.objects.create(Name="如来", Email=200000, Age=8888)
    print(person1, type(person1))
    return render(request, "student.html", {"student_queryset": student_queryset})

效果如下:

 6.3 删的实现

UserInfo.objects.filter(id=19).delete()

在views.py下的student_list方法中增加orm的删除操作,删除id=1的数据,如下

def student_list(request):
    student_queryset = models.Students.objects.all()
    # person1 = models.Students.objects.create(Name="如来", Email=200000, Age=8888)
    # print(person1, type(person1))
    person2 = models.Students.objects.filter(id=1).delete()
    print(person2, type(person2))
    return render(request, "student.html", {"student_queryset": student_queryset})

效果如下: 

 6.3 查和改的实现

filter用来查询符合条件的

User.objects.filter(id__gt=10).update(Name='white')

exclude() 方法用于查询不符合条件的数据

User.objects.objects.exclude(Name=’D’) .update(Name='white')

在views.py下的student_list方法中增加orm的filter查询操作,更改id=2数据的Name,如下

def student_list(request):
    student_queryset = models.Students.objects.all()
    # person1 = models.Students.objects.create(Name="如来", Email=200000, Age=8888)
    # print(person1, type(person1))
    # person2 = models.Students.objects.filter(id=1).delete()
    # print(person2, type(person2))
    person3 = models.Students.objects.filter(id=2).update(Name='DEV')
    print(person3, type(person3))
    return render(request, "student.html", {"student_queryset": student_queryset})

效果如下:

在views.py下的student_list方法中增加orm的exclude查询操作,更改所有不符合id=2数据的Name,如下

def student_list(request):
    student_queryset = models.Students.objects.all()
    # person1 = models.Students.objects.create(Name="如来", Email=200000, Age=8888)
    # print(person1, type(person1))
    # person2 = models.Students.objects.filter(id=1).delete()
    # print(person2, type(person2))
    # person3 = models.Students.objects.filter(id=2).update(Name='DEV')
    # print(person3, type(person3))
    person4 = models.Students.objects.exclude(id=2).update(Name='DEV')
    print(person4, type(person4))
    return render(request, "student.html", {"student_queryset": student_queryset})

效果如下: 


OK,今天的笔记就写到这里啦!

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本文为[C_yyy89]所创,转载请带上原文链接,感谢
https://blog.csdn.net/ayaxx1314/article/details/125719164