django笔记-模型数据模板呈现过程记录（多对多关系）

首先,推荐一个网址：http://www.tuicool.com/articles/BfqYz2F，因为这里的比我的要有条理，更有利于各位的理解。

以下仅为为个人一次不完整的笔记：

环境：ubuntu+terminal（前面这几步是上次的重复，可略过）

（PS：这个没有做完，有时间了我重新理一遍，做个调查问卷的例子）

1、建立工程和应用：

root@pc:/home/uu# mkdir work     建立一个文件夹，用于存放工程

root@pc:/home/uu# cd work

root@pc:/home/uu/work# django-admin.py startproject csct06     建立一个工程csct06

root@pc:/home/uu/work# cd csct06/

root@pc:/home/uu/work/csct06# django-admin.py startapp blog     建立一个应用

root@pc:/home/uu/work/csct06# ls
blog  csct06  manage.py

2、完成基本设置：

root@pc:/home/uu/work/csct06# vim csct06/settings.py 

INSTALLED_APPS = (
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'blog',                               注册自己定义的应用
)

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',           这里如果用MySQL或类似数据库，只需要更改这里的相关参数就行了
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),      参数有6个：'ENGINE'为数据库的类型，'NAME'为使用的数据库名,'USER'为管理员名字
    }                                                                ‘HOST'一般为localhost，’PORT'为数据库的端口,'PASSWORD'为数据库密码
}

root@pc:/home/uu/work/csct06# vim blog/models.py             这里用于操作数据库

from django.db import models
class Author(models.Model):                            生成两个对象：作者和书
    name = models.CharField(max_length=30)

    def __unicode__(self):
        return self.name

class Book(models.Model):
    name = models.CharField(max_length=30)
    authors = models.ManyToManyField(Author)            作者和书是多对多关系

    def __unicode__(self):
        return self.name

3、同步数据库：

root@pc:/home/uu/work/csct06# ls
blog  csct06  manage.py
root@pc:/home/uu/work/csct06# python manage.py syncdb
。。。。。
Creating tables ...
Creating table django_admin_log
Creating table auth_permission
Creating table auth_group_permissions
Creating table auth_group
Creating table auth_user_groups
Creating table auth_user_user_permissions
Creating table auth_user
Creating table django_content_type
Creating table django_session
Creating table blog_author
Creating table blog_book_authors
Creating table blog_book

You just installed Django's auth system, which means you don't have any superusers defined.
Would you like to create one now? (yes/no): yes
Username (leave blank to use 'root'): uu
Email address: uu@qw.com
Password:
Password (again):
Superuser created successfully.
Installing custom SQL ...
Installing indexes ...
Installed 0 object(s) from 0 fixture(s)

绿色部分为生成的数据库，生成的数据文件为db.sqlite3：

root@pc:/home/uu/work/csct06# ls
blog  csct06  db.sqlite3  manage.py

遇到了一个小问题,以前常用mysql的,

root@pc:/home/uu/work/csct06# sqlite3 db.sqlite3
程序“sqlite3”尚未安装。 您可以使用以下命令安装：
apt-get install sqlite3

按照提示做就行了，

#apt-get install sqlite3

。。。

root@pc:/home/uu/work/csct06# sqlite3 db.sqlite3
SQLite version 3.8.2 2013-12-06 14:53:30
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite>
好了，可以操作数据库了。

4、操作数据库：

·1查看生成的数据库表：

sqlite> .tables
auth_group                  blog_author
auth_group_permissions      blog_book
auth_permission             blog_book_authors
auth_user                   django_admin_log
auth_user_groups            django_content_type
auth_user_user_permissions  django_session
sqlite> 

·2进入解释器，对数据进行整理

1）遇到一个小问题：

root@pc:/home/uu/work/csct06# ipython manage.py shell
程序“ipython”尚未安装。 您可以使用以下命令安装：
apt-get install ipython

按照操作进行，

#apt-get install ipython

出故障了，

root@pc:/home/uu/work/csct06# ipython manage.py shell
Usage: manage.py subcommand [options] [args]

Options:
  -v VERBOSITY, --verbosity=VERBOSITY
                        Verbosity level; 0=minimal output, 1=normal output,
                        2=verbose output, 3=very verbose output
  --settings=SETTINGS   The Python path to a settings module, e.g.
                        "myproject.settings.main". If this isn't provided, the
                        DJANGO_SETTINGS_MODULE environment variable will be
                        used.
  --pythonpath=PYTHONPATH
                        A directory to add to the Python path, e.g.
                        "/home/djangoprojects/myproject".
  --traceback           Raise on exception
  --version             show program's version number and exit
  -h, --help            show this help message and exit

Type 'manage.py help <subcommand>' for help on a specific subcommand.

Available subcommands:

[auth]
    changepassword
    createsuperuser

[django]
    check
    cleanup
    compilemessages
    createcachetable
    dbshell
    diffsettings
    dumpdata
    flush
    inspectdb
    loaddata
    makemessages
    runfcgi
    shell
    sql
    sqlall
    sqlclear
    sqlcustom
    sqldropindexes
    sqlflush
    sqlindexes
    sqlinitialdata
    sqlsequencereset
    startapp
    startproject
    syncdb
    test
    testserver
    validate

[sessions]
    clearsessions

[staticfiles]
    collectstatic
    findstatic
    runserver
root@pc:/home/uu/work/csct06# ls
blog  csct06  db.sqlite3  manage.py
root@pc:/home/uu/work/csct06# ip
ip                          ipod-read-sysinfo-extended
ip6tables                   ipod-time-sync
ip6tables-apply             ippfind
ip6tables-restore           ipptool
ip6tables-save              iproxy
ipcluster                   iptables
ipcmk                       iptables-apply
ipcontroller                iptables-restore
ipcrm                       iptables-save
ipcs                        iptables-xml
ipengine                    iptunnel
iplogger                    ipython
ipmaddr                     ipython2.7
root@pc:/home/uu/work/csct06# ipython2.7 manage.py shell
/usr/lib/python2.7/dist-packages/IPython/frontend.py:30: UserWarning: The top-level `frontend` package has been deprecated. All its subpackages have been moved to the top `IPython` level.
  warn("The top-level `frontend` package has been deprecated. "
---------------------------------------------------------------------------
MultipleInstanceError                     Traceback (most recent call last)
/usr/lib/python2.7/dist-packages/IPython/utils/py3compat.pyc in execfile(fname, *where)
    202             else:
    203                 filename = fname
--> 204             __builtin__.execfile(filename, *where)

/home/uu/work/csct06/manage.py in <module>()
      8     from django.core.management import execute_from_command_line
      9
---> 10     execute_from_command_line(sys.argv)

/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.pyc in execute_from_command_line(argv)
    397     """
    398     utility = ManagementUtility(argv)
--> 399     utility.execute()

/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.pyc in execute(self)
    390             sys.stdout.write(self.main_help_text() + '\n')
    391         else:
--> 392             self.fetch_command(subcommand).run_from_argv(self.argv)
    393
    394 def execute_from_command_line(argv=None):

/usr/local/lib/python2.7/dist-packages/django/core/management/base.pyc in run_from_argv(self, argv)
    240         handle_default_options(options)
    241         try:
--> 242             self.execute(*args, **options.__dict__)
    243         except Exception as e:
    244             if options.traceback or not isinstance(e, CommandError):

/usr/local/lib/python2.7/dist-packages/django/core/management/base.pyc in execute(self, *args, **options)
    283             if self.requires_model_validation and not options.get('skip_validation'):
    284                 self.validate()
--> 285             output = self.handle(*args, **options)
    286             if output:
    287                 if self.output_transaction:

/usr/local/lib/python2.7/dist-packages/django/core/management/base.pyc in handle(self, *args, **options)
    413         if args:
    414             raise CommandError("Command doesn't accept any arguments")
--> 415         return self.handle_noargs(**options)
    416
    417     def handle_noargs(self, **options):

/usr/local/lib/python2.7/dist-packages/django/core/management/commands/shell.pyc in handle_noargs(self, **options)
     79                 raise ImportError
     80
---> 81             self.run_shell(shell=interface)
     82         except ImportError:
     83             import code

/usr/local/lib/python2.7/dist-packages/django/core/management/commands/shell.pyc in run_shell(self, shell)
     59         for shell in available_shells:
     60             try:
---> 61                 return getattr(self, shell)()
     62             except ImportError:
     63                 pass

/usr/local/lib/python2.7/dist-packages/django/core/management/commands/shell.pyc in ipython(self)
     42         for ip in (self._ipython, self._ipython_pre_100, self._ipython_pre_011):
     43             try:
---> 44                 ip()
     45             except ImportError:
     46                 pass

/usr/local/lib/python2.7/dist-packages/django/core/management/commands/shell.pyc in _ipython(self)
     36         """Start IPython >= 1.0"""
     37         from IPython import start_ipython
---> 38         start_ipython(argv=[])
     39
     40     def ipython(self):

/usr/lib/python2.7/dist-packages/IPython/__init__.pyc in start_ipython(argv, **kwargs)
    116     """
    117     from IPython.terminal.ipapp import launch_new_instance
--> 118     return launch_new_instance(argv=argv, **kwargs)
    119
    120 def start_kernel(argv=None, **kwargs):

/usr/lib/python2.7/dist-packages/IPython/config/application.pyc in launch_instance(cls, argv, **kwargs)
    542         """
    543         try:
--> 544             app = cls.instance(**kwargs)
    545             app.initialize(argv)
    546             app.start()

/usr/lib/python2.7/dist-packages/IPython/config/configurable.pyc in instance(cls, *args, **kwargs)
    358             raise MultipleInstanceError(
    359                 'Multiple incompatible subclass instances of '
--> 360                 '%s are being created.' % cls.__name__
    361             )
    362 

MultipleInstanceError: Multiple incompatible subclass instances of TerminalIPythonApp are being created.

命令出错了，因该是以下命令：

# python manage.py shell

创建四个作者：

root@pc:/home/uu/work/csct06# python manage.py shell
Python 2.7.6 (default, Mar 22 2014, 22:59:56)
。。。。
下面开始执行操作：
In [1]: from blog.models import Author,Book

In [2]: Author.objects.create(name='Tom1')    用create方法插入数据
Out[2]: <Author: Tom1>

In [3]: Author.objects.create(name='Tom2')
Out[3]: <Author: Tom2>

In [4]: Author.objects.create(name='Bob1')
Out[4]: <Author: Bob1>

In [5]: Author.objects.create(name='Bob2')
Out[5]: <Author: Bob2>

In [8]: auhtors = Author.objects.all()   这里出错了
In [9]: authors
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-9-07dd264ecf4d> in <module>()
----> 1 authors
NameError: name 'authors' is not defined
按照下面的步骤走，可以解决
直接查询所有作者：
In [11]: Author.objects.all()
Out[11]: [<Author: Tom1>, <Author: Tom2>, <Author: Bob1>, <Author: Bob2>]
通过赋值查询所有结果：
In [12]: author = Author.objects.all()
In [13]: author
Out[13]: [<Author: Tom1>, <Author: Tom2>, <Author: Bob1>, <Author: Bob2>]

In [14]: b1 = Book()       获取b1对象
In [15]: b1.name = 'Java'     添加第一本书:Java
In [16]: b1.save()                 用sava方法保存

为书Java添加作者：
In [20]: tom1 = Author.objects.get(name_exact='Tom1')
---------------------------------------------------------------------------
FieldError                                Traceback (most recent call last)
。。。
  name_exact方法出错，处理：
In [21]: tom1 = Author.objects.get(name='Tom1')
In [22]: tom1
Out[22]: <Author: Tom1>
添加第一个作者：
In [23]: b1.authors.add(tom1)
添加成功：
In [24]: b1.authors.all()
Out[24]: [<Author: Tom1>]

添加第二个作者：
In [26]: b1.authors.add(author[2])
In [27]: b1.authors.all()
Out[27]: [<Author: Tom1>, <Author: Bob1>]
第三个作者，注意一下下标：
In [28]: b1.authors.add(author[1])
In [29]: b1.authors.all()
Out[29]: [<Author: Tom1>, <Author: Tom2>, <Author: Bob1>] 
删除一个作者，调用remove方法：
In [30]: b1.authors.remove(tom1)
用all方法进行全部查询：
In [31]: b1.authors.all()
Out[31]: [<Author: Tom2>, <Author: Bob1>]
用filter方法进行局部查询：
In [31]: b1.authors.all()
Out[31]: [<Author: Tom2>, <Author: Bob1>]
这里已经删除了Tom1这个作者，所以查询不到：
In [32]: b1.authors.filter(name='Tom1')
Out[32]: []

In [33]: b1.authors.filter(name='Tom2')
Out[33]: [<Author: Tom2>]

In [34]: tom1                  tom1对象前面已经获取了
Out[34]: <Author: Tom1>

In [35]: tom1.book_set.all()    set是一个集合，也可以看成一个对象
Out[35]: []

In [36]: tom1.book_set.add(b1)    同样用add方法为作者添加一本书，就是前面的书Java

In [40]: tom1.book_set.create(name="python")  添加第二本书
Out[40]: <Book: python>

In [41]: tom1.book_set.all()                   共为tom1添加了两本书
Out[41]: [<Book: Java>, <Book: python>]

In [42]: book = Book.objects.all()    查看书的集合
In [43]: book
Out[43]: [<Book: Java>, <Book: python>]

In [44]: tom1.book_set.remove(book[0])   移除一本书

In [45]: tom1.book_set.all()
Out[45]: [<Book: python>]

5、继续上午的编辑，首先，查看上面做的结果

In [2]: from blog.models import Author,Book 首先导入两个对象作者和书

In [4]: authors = Author.objects.all()     赋值

In [5]: authors                       间接查询
Out[5]: [<Author: Tom1>, <Author: Tom2>, <Author: Bob1>, <Author: Bob2>]

In [6]: a1 = authors[0]               特定查询第一个作者的信息
In [7]: a1.book_set
Out[7]: <django.db.models.fields.related.ManyRelatedManager at 0x7f7f46e53c10>
In [9]: a1.book_set.all()[0]    详细查看作者a1出版的书的信息
Out[9]: <Book: python>

In [11]: for author in Author.objects.all():    这里通过一个复杂的结构完成类似功能 
   ....:     for book in author.book_set.all():
   ....:         print book
   ....:         
python
Java
Java
各种模块学习大全：

6、如何在web中展现

·1、首先，在blog.views.py里将数据库的内容渲染到html中

blog.views.py

#coding=utf-8
from django.shortcuts import render,render_to_response

from blog.models import Author,Book    首先导入数据库里的对象

def show_author(req):
    authors = Author.objects.all()     遍历作者信息
    return render_to_response('show_author.html',{'authors':authors})  将作者信息渲染到模板文件中

·2、然后，在应用blog目录下创建templates用来保存html

root@pc:/home/uu/work/csct06/blog# mkdir templates 
·3、其次，在templates里编辑一个show_author.html，

#vim  /blog/templates/show_author.html

先输入变量名，看能否运行：

{{authors}}

保存

·4、设置urls.py,添加映射

url(r'^blog/show_author/$','blog.views.show_author'), 保存推出：wq
·5、运行开发服务器

root@pc:/home/uu/work/csct06# python manage.py runserver
......
Django version 1.6.5, using settings 'csct06.settings'
Starting development server at http://127.0.0.1:8000/

在浏览器中运行，

·6、初步成功，接下来进一步完善

{%for author in authors%}
<li>{{author}}</li>
{%endfor%}              注意括号哪里是单括号，哪里是双括号

刷新一下，结果如下：

7、再更改：

{%for author in authors%}
<h1>{{author.name}}</h1>
{%endfor%}

结果如下：

·8、遍历书的信息

{%for author in authors%}
<div>
 <h1>{{author.name}}</h1>                 这里小结一下：变量用双括号：{{变量}}
   {%for book in author.book_set.all%}               for循环这里用但括号，且要加上%
    <li> {{book}}</li>
   {%endfor%}
</div>
{%endfor%}

效果如下：

·9、在解释器里继续操作

In [13]: tom1 = Author.objects.filter(name='Tom1')
In [14]: tom1
Out[14]: [<Author: Tom1>]http://blog.csdn.net/lcyangcss/article/details/7249961
下面这里出错了，还未解决，整理中。。。。。。
In [22]: tom1.book_set.create(name='django')
。。。。

AttributeError: 'QuerySet' object has no attribute 'book_set'

In [23]: tom1.book_set.create(name="django")
。。。。

AttributeError: 'QuerySet' object has no attribute 'book_set'