文章目录
- 用户创建
- 用户修改
- 修改用户名
- 修改密码
- 修改自己的密码
- 修改其他用户的密码
- 删除用户
- 权限管理
- 查看所有权限
- 授予权限
- 回收权限
- 权限表
- columns_priv
- procs_priv
- tables_priv
用户创建
基本格式：create user '用户名' identified by '密码';
mysql> create user 'szc' identified by 'szc123';
Query OK, 0 rows affected (0.00 sec)
使用新的用户登录、查看数据库表和自己的权限：
[root@scentos szc]# mysql -uszc -pszc123
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.00 sec)
mysql> show grants;
+-----------------------------------------+
| Grants for szc@localhost |
+-----------------------------------------+
| GRANT USAGE ON *.* TO 'szc'@'localhost' |
+-----------------------------------------+
1 row in set (0.00 sec)
可见默认情况下，普通用户的权限很小。
可以在用户名后面加上@'主机'来限制该用户登录的主机，不写为%，即不限主机：
mysql> create user 'szc'@'localhost' identified by 'szc123';
Query OK, 0 rows affected (0.00 sec)
查看所有用户的用户名和登录主机，首先切换到mysql数据库，再查看user表：
mysql> use mysql -A;
Database changed
mysql> select user, host from user;
+---------------+-----------+
| user | host |
+---------------+-----------+
| root | % |
| szc | % |
| mysql.session | localhost |
| mysql.sys | localhost |
| szc | localhost |
+---------------+-----------+
5 rows in set (0.00 sec)
当然也可以手动指定新用户的登录主机为%：
mysql> create user 'szc1'@'%' identified by 'szc123';
Query OK, 0 rows affected (0.00 sec)
用户修改
修改用户名
update用户表即可，不过要刷新一下权限才能生效：
mysql> update user set user = 'szc_new' where user = 'szc' and host = 'localhost';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
查看结果：
mysql> select user, host from user;
+---------------+-----------+
| user | host |
+---------------+-----------+
| root | % |
| szc | % |
| szc1 | % |
| mysql.session | localhost |
| mysql.sys | localhost |
| szc_new | localhost |
+---------------+-----------+
6 rows in set (0.00 sec)
修改密码
修改自己的密码
mysql> alter user user() identified by '123abc';
Query OK, 0 rows affected (0.01 sec)
或：
mysql> set password = 'abc123';
Query OK, 0 rows affected (0.00 sec)
推荐第一种方式。
修改其他用户的密码
当然得有这样的权限：
mysql> alter user 'szc'@'%' identified by '123abc';
Query OK, 0 rows affected (0.00 sec)
也可以这样：
mysql> set password for 'szc'@'%' = 'abc123';
Query OK, 0 rows affected (0.00 sec)
格式为：set password for '用户名'@'主机' = '密码';
删除用户
一般采用drop user的方式，这样即时生效：
mysql> drop user 'szc1';
Query OK, 0 rows affected (0.00 sec)
mysql> select user, host from user;
+---------------+-----------+
| user | host |
+---------------+-----------+
| root | % |
| szc | % |
| mysql.session | localhost |
| mysql.sys | localhost |
| szc_new | localhost |
+---------------+-----------+
5 rows in set (0.00 sec)
默认删除登录主机为%的用户，我们最好手动指定要删除的用户主机：
mysql> drop user 'szc_new'@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> select user, host from user;
+---------------+-----------+
| user | host |
+---------------+-----------+
| root | % |
| szc | % |
| mysql.session | localhost |
| mysql.sys | localhost |
+---------------+-----------+
4 rows in set (0.00 sec)
权限管理
查看所有权限
root用户拥有所有权限，因此可以通过root用户调用show privileges查看MySQL的所有权限：
mysql> show privileges;
+-------------------------+---------------------------------------+-------------------------------------------------------+
| Privilege | Context | Comment |
+-------------------------+---------------------------------------+-------------------------------------------------------+
| Alter | Tables | To alter the table |
| Alter routine | Functions,Procedures | To alter or drop stored functions/procedures |
| Create | Databases,Tables,Indexes | To create new databases and tables |
| Create routine | Databases | To use CREATE FUNCTION/PROCEDURE |
| Create temporary tables | Databases | To use CREATE TEMPORARY TABLE |
| Create view | Tables | To create new views |
| Create user | Server Admin | To create new users |
| Delete | Tables | To delete existing rows |
| Drop | Databases,Tables | To drop databases, tables, and views |
| Event | Server Admin | To create, alter, drop and execute events |
| Execute | Functions,Procedures | To execute stored routines |
| File | File access on server | To read and write files on the server |
| Grant option | Databases,Tables,Functions,Procedures | To give to other users those privileges you possess |
| Index | Tables | To create or drop indexes |
| Insert | Tables | To insert data into tables |
| Lock tables | Databases | To use LOCK TABLES (together with SELECT privilege) |
| Process | Server Admin | To view the plain text of currently executing queries |
| Proxy | Server Admin | To make proxy user possible |
| References | Databases,Tables | To have references on tables |
| Reload | Server Admin | To reload or refresh tables, logs and privileges |
| Replication client | Server Admin | To ask where the slave or master servers are |
| Replication slave | Server Admin | To read binary log events from the master |
| Select | Tables | To retrieve rows from table |
| Show databases | Server Admin | To see all databases with SHOW DATABASES |
| Show view | Tables | To see views with SHOW CREATE VIEW |
| Shutdown | Server Admin | To shut down the server |
| Super | Server Admin | To use KILL thread, SET GLOBAL, CHANGE MASTER, etc. |
| Trigger | Tables | To use triggers |
| Create tablespace | Server Admin | To create/alter/drop tablespaces |
| Update | Tables | To update existing rows |
| Usage | Server Admin | No privileges - allow connect only |
+-------------------------+---------------------------------------+-------------------------------------------------------+
31 rows in set (0.00 sec)
授予权限
格式：grant 权限1, 权限2, .... , 权限n，on 数据库名.表名 to 用户名@用户地址 identified by 用户密码，示例如下：
mysql> grant select, update on test.* to 'szc'@'%' identified by 'abc123';
Query OK, 0 rows affected, 1 warning (0.00 sec)
这样'szc'@'%'就有了test数据库下对所有表的查询和更新权限，该用户也跟着有了查看该数据库的权限：
[root@scentos szc]# mysql -uszc -pabc123
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.7.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| test |
+--------------------+
2 rows in set (0.00 sec)
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| emp_test |
| test1 |
| test_myisam |
| test_view |
| test_view_2 |
+----------------+
5 rows in set (0.00 sec)
mysql> select * from test1;
+--------+
| info |
+--------+
| szc |
| 测试 |
+--------+
2 rows in set (0.00 sec)
mysql> update test1 set info = 'szc1' where info = 'szc';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from test1;
+--------+
| info |
+--------+
| szc1 |
| 测试 |
+--------+
2 rows in set (0.00 sec)
mysql> delete from test1 where info = 'szc';
ERROR 1142 (42000): DELETE command denied to user 'szc'@'localhost' for table 'test1'
注意grant权限是增量的，即grant新权限不会覆盖老的权限，而是取新老权限的并集：
mysql> grant delete on test.* to 'szc'@'%' identified by 'abc123';
Query OK, 0 rows affected, 1 warning (0.00 sec)
测试：
[root@scentos szc]# mysql -uszc -pabc123
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.7.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> delete from test1 where info = 'szc1';
Query OK, 1 row affected (0.00 sec)
mysql> select * from test1;
+--------+
| info |
+--------+
| 测试 |
+--------+
1 row in set (0.00 sec)
赋予某个用户全部权限：
mysql> grant all privileges on *.* to 'szc'@'%' identified by 'abc123';
Query OK, 0 rows affected, 1 warning (0.00 sec)
但是这些权限不包括赋予权限的权限：
mysql> select * from user\G
*************************** 1. row ***************************
Host: %
User: root
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Reload_priv: Y
Shutdown_priv: Y
Process_priv: Y
File_priv: Y
Grant_priv: Y
References_priv: Y
Index_priv: Y
Alter_priv: Y
Show_db_priv: Y
Super_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Execute_priv: Y
Repl_slave_priv: Y
Repl_client_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Create_user_priv: Y
Event_priv: Y
Trigger_priv: Y
Create_tablespace_priv: Y
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions: 0
max_updates: 0
max_connections: 0
max_user_connections: 0
plugin: mysql_native_password
authentication_string: *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B
password_expired: N
password_last_changed: 2022-01-15 16:07:32
password_lifetime: NULL
account_locked: N
......
*************************** 4. row ***************************
Host: %
User: szc
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Reload_priv: Y
Shutdown_priv: Y
Process_priv: Y
File_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Show_db_priv: Y
Super_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Execute_priv: Y
Repl_slave_priv: Y
Repl_client_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Create_user_priv: Y
Event_priv: Y
Trigger_priv: Y
Create_tablespace_priv: Y
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions: 0
max_updates: 0
max_connections: 0
max_user_connections: 0
plugin: mysql_native_password
authentication_string: *6691484EA6B50DDDE1926A220DA01FA9E575C18A
password_expired: N
password_last_changed: 2022-01-15 20:30:48
password_lifetime: NULL
account_locked: N
4 rows in set (0.00 sec
回收权限
命令格式：remove 权限1, 权限2, ...., 权限n on 数据库名.表名 from 用户名@用户主机;，示例如下：
mysql> grant delete on test.test1 to 'szc'@'%' identified by 'abc123';
Query OK, 0 rows affected, 1 warning (0.00 sec)
注意，如果某个权限是以数据库名.*的名称赋予的，则必须通过一样的方式回收，而不能通过数据库名.表名回收。反过来，如果某个权限是以数据库名.表名的名称赋予的，则既可以通过库名.表名的方式回收，也可以通过库名.*的方式回收。
回收全库全表的全部权限：
mysql> revoke all privileges on *.* from 'szc'@'%';
Query OK, 0 rows affected (0.00 sec)
注意：
- 删除某个用户前，必须回收该用户的所有权限；
- 增删某个用户的权限后，该用户重新登录后方可生效。
权限表
MySQL服务器通过权限表控制用户对数据库的访问，权限表包括columns_priv、procs_privs和tables_priv，分别存储用户对列、存储函数(存储过程)和数据表的权限：
columns_priv
该表的字段如下：
mysql> desc columns_priv;
+-------------+----------------------------------------------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+----------------------------------------------+------+-----+-------------------+-----------------------------+
| Host | char(60) | NO | PRI | | |
| Db | char(64) | NO | PRI | | |
| User | char(32) | NO | PRI | | |
| Table_name | char(64) | NO | PRI | | |
| Column_name | char(64) | NO | PRI | | |
| Timestamp | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| Column_priv | set('Select','Insert','Update','References') | NO | | | |
+-------------+----------------------------------------------+------+-----+-------------------+-----------------------------+
7 rows in set (0.00 sec)
Column_priv说明了用户对某个列的操作权限，为Select、Insert、Update和References中一个或多个，分别表示查看、增加、修改和向其他表建立外键。
procs_priv
该表的字段如下：
mysql> desc procs_priv;
+--------------+----------------------------------------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+----------------------------------------+------+-----+-------------------+-----------------------------+
| Host | char(60) | NO | PRI | | |
| Db | char(64) | NO | PRI | | |
| User | char(32) | NO | PRI | | |
| Routine_name | char(64) | NO | PRI | | |
| Routine_type | enum('FUNCTION','PROCEDURE') | NO | PRI | NULL | |
| Grantor | char(93) | NO | MUL | | |
| Proc_priv | set('Execute','Alter Routine','Grant') | NO | | | |
| Timestamp | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+--------------+----------------------------------------+------+-----+-------------------+-----------------------------+
8 rows in set (0.00 sec)
Proc_priv说明了用户对某个存储过程或函数的操作权限，为Execute、Alter Routine和Grant中一个或多个，分别表示执行、修改过程体函数体和授予或回收某个用户执行权限。
tables_priv
该表的字段如下：
mysql> desc tables_priv\G
*************************** 1. row ***************************
Field: Host
Type: char(60)
Null: NO
Key: PRI
Default:
Extra:
*************************** 2. row ***************************
Field: Db
Type: char(64)
Null: NO
Key: PRI
Default:
Extra:
*************************** 3. row ***************************
Field: User
Type: char(32)
Null: NO
Key: PRI
Default:
Extra:
*************************** 4. row ***************************
Field: Table_name
Type: char(64)
Null: NO
Key: PRI
Default:
Extra:
*************************** 5. row ***************************
Field: Grantor
Type: char(93)
Null: NO
Key: MUL
Default:
Extra:
*************************** 6. row ***************************
Field: Timestamp
Type: timestamp
Null: NO
Key:
Default: CURRENT_TIMESTAMP
Extra: on update CURRENT_TIMESTAMP
*************************** 7. row ***************************
Field: Table_priv
Type: set('Select','Insert','Update','Delete','Create','Drop','Grant','References','Index','Alter','Create View','Show view','Trigger')
Null: NO
Key:
Default:
Extra:
*************************** 8. row ***************************
Field: Column_priv
Type: set('Select','Insert','Update','References')
Null: NO
Key:
Default:
Extra:
8 rows in set (0.01 sec)
Table_priv说明了用户对某个表的操作权限，为Select、Insert、Update、Delete、Create、Drop、Grant、References、Index、Alter、Create View、Show view和Trigger中一个或多个，分别表示查看表数据、增加表数据、修改表数据、删除表数据、创建表、删除表、和其他表建立外键关系、增删索引、修改表结构、创建视图、查看视图的创建状态(show create view或explain)、执行索引操作(增、删、触发或查看)。
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