centos下安装mysql服务器

项目需要就在现有的服务器上面重新安装了个mysql服务器，还挺费劲儿呢，因为之前都是在我的笔记本上面试验的，它的系统是Ubuntu的，什么路径啊，启动方式啊。都不一样所以这次还是让我纠结了一把：

下面把我安装过程中遇到的问题给传上来，

首先rpm格式安装就不多说了，主要是mysql的配置文件在：/etc/my.cnf这里，需要修改：

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Default to using old password format for compatibility with mysql 3.x
# clients (those using the mysqlclient10 compatibility package).
old_passwords=1　 ← 找到这一行，在这一行的下面添加新的规则，让MySQL的默认编码为UTF-8
default-character-set = utf8　 ← 添加这一行

然后在配置文件的文尾填加如下语句：

[mysql]
default-character-set = utf8

然后我就直接启动mysql了，还以为是Ubuntu的那样呢，安装后自动启动，可是centos不一样，服务没有启动所以就抱错了。

[root@fsailing1 init.d]# mysql -u root
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

这个错误之前遇到过，就是因为错误或者其他的什么原因，mysql服务器没有启动造成的。

接着启动mysql服务：

root@fsailing1 init.d]# /etc/rc.d/init.d/mysqld start
启动 MySQL：                                               [确定]
[root@fsailing1 init.d]# ps -ef |grep mysql
root      1949     1  0 22:21 pts/1    00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --user=mysql
mysql     2002  1949  1 22:21 pts/1    00:00:00 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock
root      2020  1101  0 22:21 pts/1    00:00:00 grep mysql

启动方式有很多种：service方式service mysqld start 和安全方式：/usr/bin/mysqld_safe &
通过启动服务的后缀我们可以清楚的看到，数据库放在那里，错误日志在哪里，
完事之后，要看看字符集的问题（这个问题至今我还没有搞清楚呢）。是否匹配：

mysql> show variables like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | latin1                     |
| character_set_connection | latin1                     |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | latin1                     |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

这种情况是不行的，我们只是改变了服务器的字符集，没有改变客户端的字符集。
修改my.cnf文件后，重启mysql服务器后得知：

mysql> show variables like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

这样就算是完成了，字符集的配置了。然后呢就是密码和授权问题了。

查看用户密码：

mysql> select host, user ,password from user;
+-----------+------+----------+
| host      | user | password |
+-----------+------+----------+
| localhost | root |          |
| fsailing1 | root |          |
| 127.0.0.1 | root |          |
| localhost |      |          |
| fsailing1 |      |          |
+-----------+------+----------+
5 rows in set (0.00 sec)

这里用户和密码有的是空的，怪不得不需要任何验证都能够登录到服务器上去，这是很不安全的。所以要删除这些不安全的用户

mysql> delete from user where user='';
Query OK, 2 rows affected (0.00 sec)

mysql> select host, user ,password from user;
+-----------+------+----------+
| host      | user | password |
+-----------+------+----------+
| localhost | root |          |
| fsailing1 | root |          |
| 127.0.0.1 | root |          |
+-----------+------+----------+
3 rows in set (0.00 sec)

然后是设置现有的用户密码：这里可以update，set都行。

mysql> update user set password='123' where host='localhost';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select host, user ,password from user;
+-----------+------+----------+
| host      | user | password |
+-----------+------+----------+
| localhost | root | 123      |
| fsailing1 | root |          |
| 127.0.0.1 | root |          |
+-----------+------+----------+
3 rows in set (0.00 sec)

这里我一看傻眼了，没有经过md5码加密呢，算了这里还只能用set进行设置密码呢。

mysql> set password for root@localhost=password('123');
Query OK, 0 rows affected (0.00 sec)

mysql> select host, user ,password from user;
+-----------+------+------------------+
| host      | user | password         |
+-----------+------+------------------+
| localhost | root | 773359240eb9a1d9 |
| fsailing1 | root |                  |
| 127.0.0.1 | root |                  |
+-----------+------+------------------+
3 rows in set (0.00 sec)

到这里该做的基本上就算是完事了。