Django与数据库MySQL连接的用法

桃扇骨 2022-07-15 03:56 241阅读 0赞

### 自己动手写Django app的教学网址:[https://my.oschina.net/davidxp/blog/109460][https_my.oschina.net_davidxp_blog_109460] ###

## 创建mysite目录 ##

`django-admin.py startproject mysite`这个命令作用是:这将创建在当前目录创建一个mysite目录

前提是从命令行上cd到你想储存你代码的目录,然后生成各种子目录.

![这里写图片描述][20161101235809263]

## 首先需要注意的是文件目录 ##

![文件目录][20161101140456999]

这里面的文件大致作用:

*  books这个 文件夹存放的是新建数据库的各种信息
 *  books/templates这个目录下装的是网页的布局,当然这个网页的布局就是show.html所提供
 *  books/views.py定义函数,并且把show.html引入进去,文件内容如下:

from django.shortcuts import render,render_to_response
    
    from django.template import loader
    
    from books import models
    
    # Create your views here.
    
    def show(request):
        # publisher_list = [{'name':"gongye",'city':'beijing'}]
        publisher_list = models.Publisher.objects.all()
        return render_to_response('show.html',{
       'publisher_list':publisher_list})

*  books/models.py文件存放的是你所创建的数据库,代码如下:

#coding=utf-8
    from __future__ import unicode_literals
    
    from django.db import models
    
    # Create your models here.
    
    class Publisher(models.Model):
        name = models.CharField(max_length = 30)
        address = models.CharField(max_length = 50)
        city = models.CharField(max_length = 60)
        state_province = models.CharField(max_length = 30)
        country = models.CharField(max_length = 50)
        website = models.URLField()
    # __unicode__这个函数用来返回某个值可以很好的用于查询和admin界面的显示
        def __unicode__(self):
            return self.name
    
    class Author(models.Model):
        first_name = models.CharField(max_length = 30)
        last_name = models.CharField(max_length = 40)
        email = models.EmailField(blank = True,verbose_name = 'e-mail')
        def __unicode__(self):
            return u'%s %s'%(self.first_name,self.last_name)
    
    class Book(models.Model):
        title = models.CharField(max_length = 100)
        author = models.ManyToManyField(Author)
        publisher = models.ForeignKey(Publisher)
        publication_date = models.DateField(blank = True,null = True)
        def __unicode__(self):
            return self.title

*  books下其他的文件就是在创建的过程中自己产生的.
 *  website/templates文件里存放的是各种显示的静态网页布局,这么多html文件,只要你在访问测试的时候,端口号后面加上html的文件名字就行.比如,我要访问templates/base.html文件,输入网址:localhost:8000/base就可以.
 *  website/settings.py文件是Django的设置文档,里面的INSTALLED\_APPS添加多个应用,比如这里面我九添加了books应用,代码如下:

INSTALLED_APPS = [
        'django.contrib.admin',
        'django.contrib.auth',
        'django.contrib.contenttypes',
        'django.contrib.sessions',
        'django.contrib.messages',
        'django.contrib.staticfiles',
        'books',
    ]

增加模板文件夹,能够引入templates,代码如下:(同样都是在settings中修改)

TEMPLATES = [
        {
            'BACKEND': 'django.template.backends.django.DjangoTemplates',
            'DIRS': ['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',
                ],
            },
        },
    ]

*  website/urls.py作用是引导url(资源管理器),代码如下:

#coding=utf-8
    """website URL Configuration The `urlpatterns` list routes URLs to views. For more information please see: https://docs.djangoproject.com/en/1.9/topics/http/urls/ Examples: Function views 1. Add an import: from my_app import views 2. Add a URL to urlpatterns: url(r'^$', views.home, name='home') Class-based views 1. Add an import: from other_app.views import Home 2. Add a URL to urlpatterns: url(r'^$', Home.as_view(), name='home') Including another URLconf 1. Import the include() function: from django.conf.urls import url, include 2. Add a URL to urlpatterns: url(r'^blog/', include('blog.urls')) """
    from django.conf.urls import *
    from django.contrib import admin
    from website.views import *
    
    urlpatterns = patterns('website.views',
        url(r'^admin/', admin.site.urls),
        (r'^$','my_homepage_view'),
        (r'^hello/$','hello'),
        (r'^time/$','current_datetime'),#显示当前时间
        (r'^time/plus/(\d{1,2})/$','hour_ahead'),#显示几小时后的时间
        (r'xiaomi/$','xiaomi'),
        (r'name/$','name'),
        (r'meta/$','display_meta'),
        )
    
    urlpatterns += patterns('books.views',
        url(r'^show/','show'),
        url(r'search_form/$','search_form'),
        url(r'search/$','search'),
    )

### 注意: urls.py与views.py文件是对应的,在views.py中定义函数,一定要添加到urls.py中去. ###

*  website/views.py文件是定义各种函数,便于使用,代码如下:

#coding=utf-8
    
    from django.http import HttpResponse
    import datetime
    
    from django.template import loader
    from django.shortcuts import render,render_to_response
    
    def hello(request):
        return HttpResponse("Hello World")
    
    def my_homepage_view(request):
        return HttpResponse("你好")
    
    def current_datetime(request):
        now = datetime.datetime.now()
        html = "<html><body>It is now %s.</body></html>"%now
        return HttpResponse(html)
    
    def hour_ahead(request,offset): #定义函数，这个函数名在urls.py文件中必须存在
        offset = int(offset)
        dt = datetime.datetime.now() + datetime.timedelta(hours = offset)
        html = "<html><body>In %s hour(s),it will be %s.</body></html>"%(offset,dt)
        return HttpResponse(html)
    
    def xiaomi(request):
        t = loader.get_template("xiaomi.html")
        html = t.render({})
        return HttpResponse(html)
    
    d = {
       'name':'zhangsan','age':'15'}  #可以引入字典
    l = ['zhangsan','14']  #引入列表
    
    #定义变量
    class A:
        age = 11
    a = A()
    
    #定义函数
    def fun():
        return "hello"
    
    def name(request):
    
        today = 1 #1代表判断正确，输出结果；0代表错误，不输出结果
        #name_list = ['zhangsan','lisi','wangwu','zhanba']
        name_list = []
    
        t = loader.get_template("name.html")
        #html = t.render({'name':'zhangjianwei'}) #直接加入值
        #html = t.render({'name':fun}) #引用函数
        html = t.render({
       'name':fun,'today_is_weekend':today,'athlete_list':name_list})
        return HttpResponse(html)
    
    def display_meta(request):
        values = request.META.items()
        values.sort()
        html= []
        path = request.path
        for (k,v) in values:
            html.append((k,v))
        return render_to_response('meta.html',{
       'meta_data':html,'request_path':path})

### 操作数据库使用到的命令: ###

*  `mysql -u root -p`连接用户名为root的数据库
 *  `show databases`显示数据库
 *  `create database Bookdb default character set utf8 collate utf8_general_ci;`创建一个Bookdb数据库并设置utf-8编码
 *  `use Bookdb;`使用Bookdb数据库
 *  `show tables;`显示数据库里的存在的项目名
 *  `select * from books_publisher;`查询books\_publisher数据库里的数据
    
    命令如图所示:  
    ![命令][20161101162634343]
    
    ![这里写图片描述][20161101162701372]

--------------------

[https_my.oschina.net_davidxp_blog_109460]: https://my.oschina.net/davidxp/blog/109460
[20161101235809263]: /images/20220715/d585ff22ee4d4cf39df482b8891c5f29.png
[20161101140456999]: /images/20220715/9c47cdf8a3ad4d0697ca72bf5efbe19b.png
[20161101162634343]: /images/20220715/f792acd9207c411f891b4ecd11d7de7f.png
[20161101162701372]: /images/20220715/bc54f278a71e4402b6f673438fb60da7.png