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

9.create database databasename default character set utf8 collate utf8_general_ci;

CREATE DATABASE databasename CHARACTER SET utf8; (推荐用这条命令)

创建一个库字符集编码为utf-8，databasename是库名

10. mysqldump -uroot -proot -d mfor > mfor.sql

将库导成.sql文件 -uroot 用户名 -proot密码 mfor 库的名字

安装PyMysql 库

在相应位置加入

10.drop database databasename;

删除数据库，databasename是库名

11.use databasename;

     show tables;

     use使用某一个库，show tables为展示这个库里面所有的表，databasename是库名。

12mac mysql error You must reset your password using ALTER USER statement before executing this statement. (mac下mysql错误)

安装完mysql 之后，登陆以后，不管运行任何命令，总是提示这个

step 1: SET PASSWORD = PASSWORD('your new password');

step 2: ALTER USER 'root'@'localhost' PASSWORD EXPIRE NEVER;

step 3: flush privileges;

完成以上三步退出再登，使用新设置的密码就行了，以上除了红色的自己修改成新密码外，其他原样输入即可

mac 登录mysql

http://jingyan.baidu.com/article/48a42057e2b2b9a9242504a2.html

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',  #默认  
        'NAME': 'mysite',  #mysql的库名称
        'USER': 'root',   #用户名
        'PASSWORD': '123456', #密码  
        'HOST': '127.0.0.1',   #默认
        'PORT': '3306',   #默认
    }  
}  

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：

在虚拟环境下安装

pip install python-mysqldb

有可能在python3下提示安装pymysql==0.7.11

pymysql的用法与MySQLdb完全相同，只要记得在新建项目下面的_init__.py文件中添加如下代码就可以了~：

import pymysql
pymysql.install_as_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)