Ununtu 15.04 安装MySql（Django连接Mysql）

本文介绍Ubuntu 15.04下安装Mysql

• ubuntu 15.04安装mysql
• django项目连接mysql

一.安装数据库

1.sudo apt-get install mysql-server  

2.apt-get install client

3.sudo apt-get install libmysqlclient-dev

安装过程中会提示输入用户密码，输入即可。

sudo netstat -tap | grep mysql

检查mysql是否安装成功，如下显示就是安装成功了。

mingwei@mingwei:~$ sudo netstat -tap | grep mysql
[sudo] password for mingwei: 
tcp        0      0 localhost:mysql         *:*                     LISTEN      23411/mysqld    
mingwei@mingwei:~$ 

4.mysql -u root -p

   进入数据库, -u是用户名，这里是root用户，-p是密码

5.show databases;

   查看所有数据库  结尾出有 “；”

6.use databasename

   使用制定的库文件  databasename是数据库名

7.show tables;

   列出所有表  结尾出有 “；”

8.create database databasename

   创建一个库，databasename是库名

创建好之后测试看库有没有，第二部分我们使用django来连接这个库试试。

二.连接数据库

接下来我们在web项目中测试连接mysql

1.在django项目的app下的的models.py下编写项目的model，然后django自身的ORM会读取这些model，并在数据库中创建相应的表，字段。

我们写的例子如下：

from django.db import models

# Create your models here.
class blogPost(models.Model):
    blog_title=models.CharField(max_length=150)
    blog_body=models.TextField()
    blog_timestamp=models.DateTimeField()

2.在web项目下的settings.py下面配置mysql数据库的连接参数

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'mysite',
        'USER': 'root',
        'PASSWORD': '123456',
        'HOST': '127.0.0.1',
        'PORT': '3306',
    }
}

3.测试连接数据库

python manage.py check

如果是这样：数据库连接失败了，查看结尾的提示，No module named MySqldb，

mingwei@mingwei:~/mysite$ python manage.py check
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
    utility.execute()
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/core/management/__init__.py", line 312, in execute
    django.setup()
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/__init__.py", line 18, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/apps/registry.py", line 108, in populate
    app_config.import_models(all_models)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/apps/config.py", line 198, in import_models
    self.models_module = import_module(models_module_name)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/contrib/auth/models.py", line 41, in <module>
    class Permission(models.Model):
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/models/base.py", line 139, in __new__
    new_class.add_to_class('_meta', Options(meta, **kwargs))
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/models/base.py", line 324, in add_to_class
    value.contribute_to_class(cls, name)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/models/options.py", line 250, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/__init__.py", line 36, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/utils.py", line 240, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/utils.py", line 111, in load_backend
    return import_module('%s.base' % backend_name)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/mingwei/.local/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 27, in <module>
    raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: No module named MySQLdb

缺少python连接数据的库，我们需要安装一下：

sudo apt-get install python-mysqldb

安装完之后再测试，如果不报错就说明安装成功了。

4.根据我我们编写的model来生成数据库

python manage.py syncdb

mingwei@mingwei:~/mysite$ python manage.py syncdb
/home/mingwei/.local/lib/python2.7/site-packages/django/core/management/commands/syncdb.py:24: RemovedInDjango19Warning: The syncdb command will be removed in Django 1.9
  warnings.warn("The syncdb command will be removed in Django 1.9", RemovedInDjango19Warning)

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

You have installed Django's auth system, and don't have any superusers defined.
Would you like to create one now? (yes/no): yes
Username (leave blank to use 'mingwei'): 
Email address: 
Password: 
Password (again): 
Error: Blank passwords aren't allowed.
Password: 
Password (again): 
Superuser created successfully.

生成了一大堆的东西，并且下面有successfully我都以为成功了，然后跑到mysql下去看，看到的是这样的，

mysite的库确实生成了，但是表并没有生成：

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysite             |
| mysql              |
| performance_schema |
+--------------------+

use mysite 进入库下面：

show tables;列出所有表，发现只有一些用户表：奇了怪了，说好的orm自动生成呢？

mysql> show tables;
+----------------------------+
| Tables_in_mysite           |
+----------------------------+
| auth_group                 |
| auth_group_permissions     |
| auth_permission            |
| auth_user                  |
| auth_user_groups           |
| auth_user_user_permissions |
| django_admin_log           |
| django_content_type        |
| django_migrations          |
| django_session             |
+----------------------------+

然后发现了是这个原因导致的，删掉你app项目下的 migrations文件夹，重新python manage.py syncdb,  哇。。。数据库奇迹般的生成了,,,,,如下表：bolg_bolgpost

mysql> show tables;
+----------------------------+
| Tables_in_mysite           |
+----------------------------+
| auth_group                 |
| auth_group_permissions     |
| auth_permission            |
| auth_user                  |
| auth_user_groups           |
| auth_user_user_permissions |
| blog_blogpost              |
| django_admin_log           |
| django_content_type        |
| django_migrations          |
| django_session             |
+----------------------------+
11 rows in set (0.00 sec)