定义数据模型&访问数据库

定义数据模型

一、Django定义数据模型在App中的models.py文件，数据库的表名称以类的形式来定义：

[root@133 web]# cd /opt/python/django/web/blog/[root@133 blog]# vim models.pyfrom django.db import models# Create your models here.class Host(models.Model):    hostname = models.CharField(max_length = 50)    ip = models.IPAddressField()

二、查看模型的语法和逻辑是否正确：python manage.py validate , 0 errors 没有语法错误

[root@133 blog]# cd /opt/python/django/web[root@133 web]# lsblog  db.sqlite3  manage.py  web[root@133 web]# python manage.py validate0 errors found

三、管理数据库

初始化数据模型到数据库：python manage.py syncdb (默认使用的slqite数据库，在setting.py可以看到)

[root@133 web]# cd /opt/python/django/web/web/[root@133 web]# vim settings.pyimport osBASE_DIR = os.path.dirname(os.path.dirname(__file__))#base_dir是seting.py的上级目录的上级目录：/opt/python/django/web/DATABASES = {    'default': {        'ENGINE': 'django.db.backends.sqlite3',        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),    }}前提是安装sqlite[root@133 web]# cd  /opt/python/django/web/[root@133 web]# python manage.py dbshellSQLite version 3.6.20Enter ".help" for instructionsEnter SQL statements terminated with a ";"sqlite> .tablessqlite> .exit#后台演示同步数据库的时候数据库的创建过程，[root@133 web]# python manage.py sqlall blogBEGIN;CREATE TABLE "blog_host" (    "id" integer NOT NULL PRIMARY KEY,    "hostname" varchar(50) NOT NULL,    "ip" char(15) NOT NULL);COMMIT;#同步数据库，会创建表blog_host，创建管理用户[root@133 web]# python manage.py syncdb  Creating tables ...Creating table django_admin_logCreating table auth_permissionCreating table auth_group_permissionsCreating table auth_groupCreating table auth_user_groupsCreating table auth_user_user_permissionsCreating table auth_userCreating table django_content_typeCreating table django_sessionCreating table blog_hostYou just installed Django's auth system, which means you don't have any superusers defined.Would you like to create one now? (yes/no): yesUsername (leave blank to use 'root'): root  #创建管理用户Email address: david-dai@zamplus.com       ＃输入管理用户的邮箱Password:                                   #输入管理用户的密码Password (again): Superuser created successfully.  Installing custom SQL ...Installing indexes ...Installed 0 object(s) from 0 fixture(s)[root@133 web]# ll总用量 48drwxr-xr-x 3 root root  4096 1月   3 09:50 blog-rw-r--r-- 1 root root 34816 1月   3 10:12 db.sqlite3  #大小不为0-rwxr-xr-x 1 root root   246 1月   1 23:11 manage.pydrwxr-xr-x 2 root root  4096 1月   3 10:02 web

查看数据库

方法一：通过admin的页面查看数据库

1、启动django

[root@133 web]# nohup python manage.py runserver 11.65.140.13:8080 &

2、在chrome浏览器中访问：输入用户名root和密码，默认是看不到数据库，需要把表注册到admin.py中，admin才能识别

[root@133 blog]# cd /opt/python/django/web/blog/[root@133 blog]# vim admin.pyfrom django.contrib import adminfrom blog.models import Host           ＃加载app应用models# Register your models here.class HostAdmin(admin.ModelAdmin):    list_display = ['hostname', 'ip']  #固定属性，类似表中的字段admin.site.register(Host,HostAdmin)    ＃注册两个表，刷新网页，多了一个host列，点击增加一个host，输入主机名和IP，点击保存，多了一个主机，可以查看

方法二：命令行方式登录查看数据库

[root@133 blog]# cd /opt/python/django/web/[root@133 web]# ll总用量 52drwxr-xr-x 3 root root  4096 1月   3 10:28 blog-rw-r--r-- 1 root root 34816 1月   3 10:32 db.sqlite3-rwxr-xr-x 1 root root   246 1月   1 23:11 manage.py-rw------- 1 root root  2125 1月   3 10:37 nohup.outdrwxr-xr-x 2 root root  4096 1月   3 10:02 web[root@133 web]# sqlite3 db.sqlite3 SQLite version 3.6.20Enter ".help" for instructionsEnter SQL statements terminated with a ";"sqlite> .tablesauth_group                  auth_user_user_permissionsauth_group_permissions      blog_host                 auth_permission             django_admin_log          auth_user                   django_content_type       auth_user_groups            django_session            sqlite> select * from blog_host;1|132|112.65.140.132sqlite>.exit[root@133 web]# python manage.py dbshellsqlite> .tablesauth_group                  auth_user_user_permissionsauth_group_permissions      blog_host                 auth_permission             django_admin_log          auth_user                   django_content_type       auth_user_groups            django_session   sqlite> select * from blog_host;1|132|112.65.140.132

访问数据库（一）

1、命令行的交互式方法（类似ipython登陆）：

＃命令行交互式登录[root@133 web]# python manage.py shell/opt/amos/python2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py:58: RuntimeWarning: SQLite received a naive datetime (2017-01-03 15:11:34.737126) while time zone support is active.  RuntimeWarning)Python 2.7.3 (default, Jan  1 2017, 21:43:50) Type "copyright", "credits" or "license" for more information.IPython 5.1.0 -- An enhanced Interactive Python.?         -> Introduction and overview of IPython's features.%quickref -> Quick reference.help      -> Python's own help system.object?   -> Details about 'object', use 'object??' for extra details.In [1]: import sysIn [2]: sys.pathOut[2]: ['', '/opt/python/django/web',            ＃项目的路径/opt/python/django/web成为环境变量 …… ……＃导入表 In [3]: from blog.models import Host  #blog 包中的modes.py文件，倒入类class：Host In [5]: Host.objects.all()    Out[5]: []         ＃返回是一个列表［］，每个元素是一个class＃显示数据In [6]: nodes = Host.objects.all() In [7]: nodes.values()                 #查看表中的内容Out[7]: [{'ip': u'112.65.140.132', 'hostname': u'132', u'id': 1}]＃增加数据添加一个hostIn [8]: Host(hostname='node02',ip='192.168.1.2')Out[8]: In [9]: n =Host(hostname='node02',ip='192.168.1.2') ＃实例化一个对象In [10]: n.save()                                   ＃保存nIn [11]: nodes = Host.objects.all()In [12]: nodes.values()Out[12]: [{'ip': u'112.65.140.132', 'hostname': u'132', u'id': 1}, {'ip': u'192.168.1.2', 'hostname': u'node02', u'id': 2}] 另一种方法添加一个hostIn [13]: n = Host()In [18]: n.hostname = 'node03'In [19]: n.ip = '192.168.1.3'In [20]: n.save()                  ＃写入表In [21]: nodes = Host.objects.all()In [22]: nodes.values()Out[22]: [{'ip': u'112.65.140.132', 'hostname': u'132', u'id': 1}, {'ip': u'192.168.1.2', 'hostname': u'node02', u'id': 2}, {'ip': u'192.168.1.3', 'hostname': u'node03', u'id': 3}]浏览器查看多了一个node03In [23]: n1 = nodes[0]In [24]: n1.hostnameOut[24]: u'132'In [25]: n1.ip Out[25]: u'112.65.140.132'In [26]: n1.ip = '192.168.1.1' #直接修改n1的ip值In [29]: n1.save()浏览器刷新可以看到主机132的ip已经变为192.168.1.1In [3]: from blog.models import HostIn [4]: nodes = Host.objects.all()In [5]: nodes.values()Out[5]: [{'ip': u'192.168.1.1', 'hostname': u'132', u'id': 1}, {'ip': u'192.168.1.2', 'hostname': u'node02', u'id': 2}, {'ip': u'192.168.1.3', 'hostname': u'node03', u'id': 3}]In [6]: for i in nodes: print i.hostname132node02node03In [7]: for i in nodes: print i.hostname,i.ip132 192.168.1.1node02 192.168.1.2node03 192.168.1.3

2、访问数据库二

通过视图文件views.py来访问数据

1、在urls.py文件里定义urls访问路径

[root@133 web]# cd /opt/python/django/web/web[root@133 web]# vim urls.pyfrom django.conf.urls import patterns, include, urlfrom django.contrib import adminadmin.autodiscover()urlpatterns = patterns('',    # Examples:    # url(r'^$', 'web.views.home', name='home'),    # url(r'^blog/', include('blog.urls')),    url(r'^admin/', include(admin.site.urls)),    url(r'^blog/index/$', 'blog.views.index'),    url(r'^db/$','blog.views.db'),             #增加url配置文件)

2、在views.py里定义访问方法

[root@133 web]# cd /opt/python/django/web/blog/[root@133 blog]# vim views.pyfrom django.shortcuts import renderfrom django.http import HttpResponsefrom django.template import loader, Contextfrom blog.models import Host   ＃从blog.models导入Host# Create your views here.def index(request):    t = loader.get_template('index.html')    c = Context({})    return HttpResponse(t.render(c))def db(req):    h = Host()    h.hostname = 'nodes04'    h.ip = '192.168.1.4'    h.save()    return HttpResponse('OK')

网页访问：http://11.65.140.13:8080/db/ 返回ok

注意：

request或者req是形式参数，形参可以随便定义，不是非得叫request或者req，可以叫abc。

访问数据库（三）／数据库传递post和get

定义API

1、urls.py

2、views.py定义访问方法（API）

[root@133 blog]# vim views.pyfrom django.shortcuts import renderfrom django.http import HttpResponsefrom django.template import loader, Contextfrom blog.models import Host# Create your views here.def index(request):    t = loader.get_template('index.html')    c = Context({})    return HttpResponse(t.render(c))def db(req):    h = Host()    h.hostname = 'nodes04'    h.ip = '192.168.1.4'    h.save()    return HttpResponse('OK')#添加collect方法def collect(request):    #if request.method == 'POST':    if request.POST:        hostname = request.POST.get('hostname')        ip = request.POST.get('ip')        host = Host()        host.hostname = hostname        host.ip = ip        host.save()        return HttpResponse('OK,OK')    else:        return HttpResponse('not data')        #修改collect转发规则[root@133 web]# cd /opt/python/django/web/web/[root@133 web]# vim urls.pyfrom django.conf.urls import patterns, include, urlfrom django.contrib import adminadmin.autodiscover()urlpatterns = patterns('',    # Examples:    # url(r'^$', 'web.views.home', name='home'),    # url(r'^blog/', include('blog.urls')),    url(r'^admin/', include(admin.site.urls)),    url(r'^blog/index/$', 'blog.views.index'),    url(r'^db/$','blog.views.db'),    url(r'^collect/$','blog.views.collect'),  ＃增加collect转发规则)      浏览器访问：http://11.65.140.13:8080/collect/  返回：not data需要修改setting文件，注释中间件，才能使用curl传数据，否则django不识别[root@133 web]# vim settings.py#    'django.middleware.csrf.CsrfViewMiddleware',＃使用－d参数post方法传hostname和ip[root@133 blog]# curl -d hostname='node05' -d ip='192.168.1.5' http://112.65.140.133:8080/collect/OK,OK                    服务器端会用get方法提取hostname和ip，然后保存。 可以查看到node05

通过get方法，先修改配置，然后通过浏览器传递。get方法是明文的，不是很安全

[root@133 blog]# vim views.pyfrom django.shortcuts import renderfrom django.http import HttpResponsefrom django.template import loader, Contextfrom blog.models import Host# Create your views here.def index(request):    t = loader.get_template('index.html')    c = Context({})    return HttpResponse(t.render(c))def db(req):    h = Host()    h.hostname = 'nodes04'    h.ip = '192.168.1.4'    h.save()    return HttpResponse('OK')def collect(request):    #if request.method == 'POST':    if request.POST:        hostname = request.POST.get('hostname')        ip = request.POST.get('ip')        host = Host()        host.hostname = hostname        host.ip = ip        host.save()        return HttpResponse('OK,OK')    elif: request.method == 'GET':            ＃定义get方法        hostname = request.GET.get('hostname')        ip = request.GET.get('ip')        host = Host()        host.hostname = hostname        host.ip = ip        host.save()        return HttpResponse('OK...')    else:        return HttpResponse('not data')

浏览器访问，指定hostname＝node07，ip＝192.168.1.7：

http://11.65.140.13:8080/collect/?hostname=node07&ip=192.168.1.7

返回：OK...

http://11.65.140.13:8080/admin/blog/host/

发现host07已经存在，使用浏览器的get方法传数据成功，明文，数据量小