Mysql基本操作总结

数据库的基本操作

1.创建数据库

# create database xxx;

2.查看数据库

# show databases;

3.删除数据库

# drop database xxx;

4.使用/切换数据库

# use xxx；

5.退出数据库

# exit;

表的基本操作

1.查看数据库中所有的表

# show tables;

2.创建表

# create table xxx;

3.查看表结构

# desc xxx;

4.查看表详细结构

# show create table xxx;

5.删除表

# drop table xxx;

6.修改表名

# alter table xxx rename yyy;

7.修改字段的数据类型

# alter table 表名 modify 属性名 新数据类型; (注意外键不能改)
# alter table B modify user_name char(50);

8.修改字段名与数据类型

# alter table 表名 change 旧属性名 新属性名 数据类型;
# alter table GG change user_name your_name char(50);

9.增加字段

# alter table 表明 add 新字段名 数据类型
# alter table GG add phone varchar(20);
# alter table GG add age int(4) not null;
# alter table GG add address varchar(30) not null after phone;

10.删除字段

# alter table GG drop age;

11.删除某条记录

# delete from 表名 where 条件
# delete from 表名                 //删除所有记录

12.修改表的存储引擎

# alter table A engine=MyISAM;

13.删除表的外键约束

# alter table 表名 drop foreign key 外键别名
# alter table yy2 drop foreign key y_fk;

14.删除表

# drop table xxx;
删除父表：先删除所有关联子表的外键，再删除父表

用户登录与管理相关操作

1. 创建用户

-> create user 'test1'@'localhost'identified by '123456';
-> create user 'test2'@'localhost'identified by 'PASSWORD(123456)';
-> insert into mysql.user(Host,User,Password,ssl_cipher,x509_issuer,x509_subject)values('hostname','test3',PASSWORD('123456'),'','','');

2. 查看用户信息

-> select Host,User,Password from mysql.user where User='test1' or User='test2' or User='test3';
+-----------+-------+-------------------------------------------+
| Host | User | Password |
+-----------+-------+-------------------------------------------+
| localhost | test1 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| localhost | test2 | *A4734F92867FE18E0DD415197D5C33D2E705F0DC |
| hostname | test3 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+-----------+-------+-------------------------------------------+

3. 删除用户

-> drop user 'test2'@'localhost';
-> delete from mysql.user where Host='localhost' and User='test3';

4. 修改root用户密码

# mysqladmin -u root -p password '新密码'
  Enter password:                   --->在这里要输入正确的旧密码

-> update mysql.user set Password=PASSWORD('新密码') where User='root' and Host='localhost';

5. 修改普通用户密码

# mysql -u test1 -p
-> set password=PASSWORD('aixocm');

-> set password for 'test1'@'localhost'=PASSWORD('aixocm');

6. 解决忘记root用户密码问题

# /etc/init.d/mysqld start --skip-grant-tables
# mysql -u root -p   --->这样可以无密码登陆进去了
-> update mysql.user set Password=PASSWORD('新密码') where User='root' and Host='localhost';

用户权限管理操作

1. 添加权限

grant 权限
on 数据库名.表名
to 'username'@'Host'

//新建用户并增加权限
grant select,update
-> on *.* --->对所有数据库的所有表
-> to 'test5'@'localhost' identified by 'aixocm' 
-> with grant option;

grant delete 
-> on *.*
-> to 'test5'@'localhost' 
-> with grant option;

2. 取消权限

revoke delete
-> on *.*
-> from 'test5'@'localhost';

//取消所有权限
revoke all privileges,grant option from 'test5'@'localhost';

3. 查看权限

-> select User,Host,Select_priv,Update_priv,Delete_priv from mysql.user where User='test5';
+-------+-----------+-------------+-------------+-------------+
| User | Host | Select_priv | Update_priv | Delete_priv |
+-------+-----------+-------------+-------------+-------------+
| test5 | localhost |    Y  |     Y       |      Y      |
+-------+-----------+-------------+-------------+-------------+

-> show grants for 'root'@'localhost'G;
*************************** 1. row ***************************
Grants for root@localhost: GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*5DBA547161E5D9C6508C3C6CF5D1B26940E3BC13' WITH GRANT OPTION
*************************** 2. row ***************************
Grants for root@localhost: GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION

4.刷新(加载)权限

-> flush privileges;

存储引擎相关操作

1.查看数据库支持的存储引擎

# show engines;
# show enginesG;
Engine:名称
Support:是否支持(YES/DEFAULT)
Comment:说明
Transaction:是否支持事务
XA:是否支持分布式交易处理的XA规范
savapoint:是否支持保存点

2.查看存储引擎详细信息

# show engine innodb statusG;

3.查看默认存储引擎 

# show variables like 'storage_engine';

4.修改默认存储引擎

# vim /etc/my.cnf(配置文件)
default-storage-engine=xxx