django提供了非常方便的数据模型，可以非常简易的设计时间结构，URL结构，输入框等等，django都已经有编写好的数据结构，对于我这种初级编程来说再好没有，否则我就要自己写数据约束，格式，出错等

对于一个博客系统最基本包含三个要素，“作者”， “博客”，“标签”

#/myblog/myblog/blog/models.py  1 from django.db import models                                                                            2                                                                                                         3 # Create your models here.                                                                              4                                                                                                         5 class Author(models.Model):                                          #作者信息                                                                         6     """docstring for Author"""                                                                          7     name = models.CharField(max_length=30)                                                              8     email = models.EmailField(blank=True)                                                               9     website = models.URLField(blank=True)                                                              10                                                                                                        11     def __unicode__(self):                                           #方便查询时返回一个名字，否则是一个实例                                  12         return self.name                                                                               13                                                                                                        14 class Tag(models.Model):                                             #标签                                                                            15     """tag of book"""                                                                                  16     tag_name = models.CharField(max_length = 30)                                                       17     create_time = models.DateTimeField(auto_now_add =True )                                            18                                                                                                        19     def __unicode__(self):                                                                             20         return self.tag_name                                                                           21                                                                                                        22 class blog(models.Model):                                            #博客                                  23     title = models.CharField(max_length=50)                          #标题                                  24     author = models.ForeignKey(Author)                               #作者 作者与博客是一对多的关系，一个博客只有一个作者，一个作者可以有多个博客                                 25     tags = models.ManyToManyField(Tag, blank=True)                   #标签 标签与博客是多对多的关系，一个博客有多个标签，一个标签也可以有多个博客，因此初始化时不能直接赋值，它是一个列表                                 26     content = models.TextField()                                     #内容                                  27     date_time = models.DateTimeField(auto_now_add = True)                                              28                                                                                                        29     def __unicode__(self):                                                                             30         return self.title                                                                              31                                                                                                        32     class Meta:                                                                                        33         ordering = ['-date_time']                                    #按照时间排序                                  34                                        

后台所对应的数据结构

同步数据库

[root@hding myblog]# python manage.py migrateOperations to perform:  Synchronize unmigrated apps: staticfiles, messages  Apply all migrations: admin, contenttypes, auth, sessionsSynchronizing apps without migrations:  Creating tables...    Running deferred SQL...  Installing custom SQL...Running migrations:  Rendering model states... DONE  Applying contenttypes.0001_initial... OK  Applying auth.0001_initial... OK  Applying admin.0001_initial... OK  Applying contenttypes.0002_remove_content_type_name... OK  Applying auth.0002_alter_permission_name_max_length... OK  Applying auth.0003_alter_user_email_max_length... OK  Applying auth.0004_alter_user_username_opts... OK  Applying auth.0005_alter_user_last_login_null... OK  Applying auth.0006_require_contenttypes_0002... OK  Applying sessions.0001_initial... OK

django 1.8.8 与 django 1.6 以前在models的重大改变在于如果你更改了数据库中的字段，你可以通过makemigrations更改，而在1.6以前一旦syncdb之后如果还需要加字段则只能在数据库中通过SQL语方直接进行操作，不能通过django实现，如现在把类blog改成类Blog

[root@hding myblog]# python manage.py  makemigrationsMigrations for 'blog':  0001_initial.py:    - Create model Author    - Create model Blog    - Create model Tag    - Add field tags to blog[root@hding myblog]# python manage.py migrateOperations to perform:  Synchronize unmigrated apps: staticfiles, messages  Apply all migrations: admin, blog, contenttypes, auth, sessionsSynchronizing apps without migrations:  Creating tables...    Running deferred SQL...  Installing custom SQL...Running migrations:  Rendering model states... DONE  Applying blog.0001_initial... OK

数据在shell中的调试

[root@hding myblog]# python manage.py shellPython 2.7.11 (default, Feb  4 2016, 07:16:42) [GCC 4.1.2 20080704 (Red Hat 4.1.2-44)] on linux2Type "help", "copyright", "credits" or "license" for more information.(InteractiveConsole)>>> from blog.models import Blog>>> from blog.models import Author>>> from blog.models import Tag#增加创建数据>>> author_1 = Author.objects.create(name ='terry') >>> author_1
    
     >>> tag_1 = Tag.objects.create(tag_name='python')>>> tag_1
     
      >> blog_1 = Blog.objects.create(title = 'hello world',...                              author = author_1,...                              content = 'this is a first web site for me')>>> blog_1
      
       >>> blog_1.tags.all()[]#给blog 增加tag>>> blog_1.tags.add(tag_1)>>> blog_1.tags.all()[
       
        ]>>> blog_1.date_timedatetime.datetime(2016, 2, 10, 7, 43, 2, 448507, tzinfo=
        
         )              #时间自动添加#简易创建方法直接对象实例化，但必需save，否则没有写进数据库，而用Author.objects.create()则是直接写到数据库中>>> author_2 = Author(name='sumsan')  >>> author_2
         
          >>> author_2.save() #必需save()才能确保写进数据库里#查询单个数据和所有数据>>> Author.objects.all()[
          
           , 
           
            ]>>> author= Author.objects.get(name='terry') #author为查到的名字为terry的实例>>> author
            
             >>> author_1
             
              #创建由terry写的第二个博客>>> blog_2 = Blog.objects.create(title='django',author=author_1,content='django is so easy to use')>>> Blog.objects.all()[
              
               , 
               
                ]#查询terry写的所有博客>>> author_1.blog_set.all()[
                
                 , 
                 
                  ]#查询terry写的博客中题目为django的博客>>> author_1.blog_set.get(title='django')
                  
                    #新建tag_2,tag_3>>> tag_2 = Tag(tag_name='django')>>> tag_2.save()>>> tag_3 = Tag.objects.create(tag_name='socket')>>> Tag.objects.all()[
                   
                    , 
                    
                     , 
                     
                      ]#blog_1增加django标签>>> blog_1.tags.add(tag_2)#blog_2增加django标签>>> blog_2.tags.add(tag_2)#查询含有django标签的博客>>> tag_2.blog_set.all()[
                      
                       , 
                       
                        ]#查询blog_1含有的标签>>> blog_1.tags.all()     [
                        
                         , 
                         
                          ]#过滤查询>>> blog_1.tags.filter(tag_name__icontains='dj')[
                          
                           ]>>> blog_1.tags.filter(tag_name__iexact='django')[
                           
                            ]#删除操作>>> blog_1.tags.filter(tag_name__iexact='django').delete()>>> blog_1.tags.filter(tag_name__iexact='django')[]
                           
                          
                         
                        
                       
                      
                     
                    
                   
                  
                 
                
               
              
             
            
           
          
         
        
       
      
     
    

在shell建立的数据在哪呢，可以在django自定义的admin后台看到

#新建超极用户[root@hding myblog]# python manage.py createsuperuserUsername (leave blank to use 'root'): rootEmail address: root@a.comPassword: Password (again): Superuser created successfully.

修改admin.py，只有在后台注册了，才能在admin后台进行管理

/myblog/myblog/blog/admin.py    1 from django.contrib import admin                                                                        2                                                                                                         3 # Register your models here.                                                                            4 from blog.models import Author,Tag,Blog                                                                 5                                                                                                         6 class AuthorAdmin(admin.ModelAdmin):                     #定制Author界面                                                                7     list_display=('name','email','website')              #分为name,email,website三列进行显示                                               8     search_field=('name')                                                                               9                                                                                                        10 class BlogAdmin(admin.ModelAdmin):                       #定制Blog界面 11     list_display = ('title','author','date_time')                                                      12     list_filter = ('date_time',)                         #按照时间进行查看                                                                                                                    15     filter_horizontal=('tags',)                          #tag水平选择                                              16                                                                                                        17 admin.site.register(Author, AuthorAdmin)                 #注册                                                18 admin.site.register(Blog,BlogAdmin)                                                                    19 admin.site.register(Tag)                                                                              ~

老界面

             

定制后的界面

定制后的界面能够更加直观的看到内部的数据，admin也是可以自定义的，这是我们管理后台数据的地方，可以通过admin对数据库的数据进行增删改查，更加方便