简易博客开发（2）----models, admin
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 migrate
Operations to perform:
Synchronize unmigrated apps: staticfiles, messages
Apply all migrations: admin, contenttypes, auth, sessions
Synchronizing 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 makemigrations
Migrations 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 migrate
Operations to perform:
Synchronize unmigrated apps: staticfiles, messages
Apply all migrations: admin, blog, contenttypes, auth, sessions
Synchronizing 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 shell Python 2.7.11 (default, Feb 4 2016, 07:16:42) [GCC 4.1.2 20080704 (Red Hat 4.1.2-44)] on linux2 Type "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 <Author: terry> >>> tag_1 = Tag.objects.create(tag_name='python') >>> tag_1 <Tag: python> >> blog_1 = Blog.objects.create(title = 'hello world', ... author = author_1, ... content = 'this is a first web site for me') >>> blog_1 <Blog: hello world> >>> blog_1.tags.all() [] #给blog 增加tag >>> blog_1.tags.add(tag_1) >>> blog_1.tags.all() [<Tag: python>] >>> blog_1.date_time datetime.datetime(2016, 2, 10, 7, 43, 2, 448507, tzinfo=<UTC>) #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: sumsan> >>> 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: terry>, <Author: sumsan>] >>> author= Author.objects.get(name='terry') #author为查到的名字为terry的实例 >>> author <Author: terry> >>> author_1 <Author: terry> #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() [<Blog: hello world>, <Blog: django>] #查询terry写的所有博客 >>> author_1.blog_set.all() [<Blog: hello world>, <Blog: django>] #查询terry写的博客中题目为django的博客 >>> author_1.blog_set.get(title='django') <Blog: 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() [<Tag: python>, <Tag: django>, <Tag: socket>] #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() [<Blog: hello world>, <Blog: django>] #查询blog_1含有的标签 >>> blog_1.tags.all() [<Tag: python>, <Tag: django>] #过滤查询 >>> blog_1.tags.filter(tag_name__icontains='dj') [<Tag: django>] >>> blog_1.tags.filter(tag_name__iexact='django') [<Tag: 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 createsuperuser Username (leave blank to use 'root'): root Email address: [email protected] Password: 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