Centos 升级MySQL版本或者Yum安装Mysql5.6
- 1.从MySQL Yum仓库下载最新的rpm文件：
http://dev.mysql.com/downloads/repo/yum/
CentOS 6
http://repo.mysql.com/mysql-community-release-el6-5.noarch.rpm - 2.yum remove mysql mysql-*
- 3.mysql-community-release-el6-5.noarch.rpm
- 4.yum localinstall mysql-community-release-el6-5.noarch.rpm
- 5.可以通过下面的命令来确认这个仓库被成功添加：
yum repolist enabled | grep "mysql.-community." - 6.yum install mysql-community-server
设置currenttime
http://www.metsky.com/archives/118.html
参考文件：
http://blog.csdn.net/shootyou/article/details/8236886
记得删除老版本的/etc/my.conf,/var/lib/mysql, 或者备份老版本的mysql
否则可能会起动不起来
http://www.th7.cn/db/mysql/201408/66691.shtml
修改用户密码：
update mysql.user set password=password("新密码") where User="root";
flush privileges;
// windows
修改登录密码 MySQL默认没有密码，安装完毕增加密码的重要性是不言而喻的。
1、命令 /usr/bin/mysqladmin -u root password 'new-password'**
格式：
mysqladmin -u用户名 -p旧密码 password 新密码**
2、例子 例1：给root加个密码123456。
键入以下命令 ：
[root@test1 local]# /usr/bin/mysqladmin -u root password 123456
创建数据库：
CREATE DATABASE `test2` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
修改my.cnf文件（mysql 减少内存使用）
# Example mysql config file for small systems.
#
# This is for a system with little memory (<= 64M) where MySQL is only used
# from time to time and it's important that the mysqld deamon
# doesn't use much resources.
#
# You can copy this file to
# /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options (in this
# installation this directory is /var/lib/mysql) or
# ~/.my.cnf to set user-specific options.
#
# One can in this file use all long options that the program supports.
# If you want to know which options a program support, run the program
# with --help option.
# The following options will be passed to all MySQL clients
[client]
#password = your_password
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
port = 3306
socket = /var/run/mysqld/mysqld.sock
character-set-server=utf8
key_buffer = 16K
query_cache_limit = 256K
query_cache_size = 4M
max_allowed_packet = 1M
max_connections = 16
thread_concurrency = 2
sort_buffer_size = 64K
read_buffer_size = 256K
read_rnd_buffer_size = 256K
net_buffer_length = 2K
thread_stack = 64K
performance_schema_max_table_instances=400
table_definition_cache=400
table_open_cache=256
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
#safe-updates
[isamchk]
key_buffer = 8M
sort_buffer_size = 8M
[myisamchk]
key_buffer = 8M
sort_buffer_size = 8M
[mysqlhotcopy]
interactive-timeout
# Uncomment the following if you want to log updates
#log-bin
# Uncomment the following if you are NOT using BDB tables
#skip-bdb
# Uncomment the following if you are using Innobase tables
#innodb_data_file_path = ibdata1:100M
#innodb_data_home_dir = /var/lib/mysql/
#innodb_log_group_home_dir = /var/lib/mysql/
#innodb_log_arch_dir = /var/lib/mysql/
#set-variable = innodb_mirrored_log_groups=1
#set-variable = innodb_log_files_in_group=3
#set-variable = innodb_log_file_size=5M
#set-variable = innodb_log_buffer_size=8M
#innodb_flush_log_at_trx_commit=1
#innodb_log_archive=0
#set-variable = innodb_buffer_pool_size=16M
#set-variable = innodb_additional_mem_pool_size=2M
#set-variable = innodb_file_io_threads=4
#set-variable = innodb_lock_wait_timeout=50
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
字符编码
查看字符编码： status
1.关于MySQL字符集
MySQL的字符集支持(Character Set Support)有两个方面：
字符集(Character set)和排序方式(Collation)。
MySQL对于字符集的支持细化到四个层次: 服务器(server)，数据库(database)，数据表(table)和连接(connection)。
MySQL对于字符集的指定可以细化到一个数据库，一张表，一列，应该用什么字符集。
2.查看MySQL字符集
2.1.查看字符集的设置
mysql> show variables like 'character_set_%';
2.2.查看字符集排序设置
mysql> show variables like 'collation_%';
3.修改MySQL字符集
3.1修改服务器级别字符集
a.临时修改
mysql>SET GLOBAL character_set_server=utf8;
b.永久修改
打开/etc/mysql/my.cnf,在[mysqld]后添加character-set-server=utf8
3.2修改数据库级
a. 临时更改
mysql>SET GLOBAL character_set_database=utf8;
b. 永久更改
改了服务器级就可以了
3.3修改表级
mysql>ALTER TABLE table_name DEFAULT CHARSET utf8; 更改了后永久生效
3.4修改列级修改示例
mysql>ALTER TABLE `products` CHANGE `products_model` VARCHAR( 20 ) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL; 更改了后永久生效
3.5更改连接字符集
a. 临时更改：mysql> SET GLOBAL character_set_client;
b. 永久更改：打开/etc/mysql/my.cnf,在[client]后添加default-character-set=utf8
Notice:3.1和3.5需要重启mysql: service mysql restart
重起mysql
service mysqld restart
转：http://www.blogjava.net/nkjava/archive/2014/11/21/420406.html
