mysql06---权限控制

mysql权限管理：
mysql的权限控制，首先在user表判断有没有权限连，连上后看有没有全局权限。然后看db表有哪些库级别的权限。然后看tables_priv表有哪些表级别的权限。最后还可以看有哪些列级别的权限。

mysql权限检查：
1.有没有权连接上来
2.有没有权执行操作（crud）

服务器是如何判断用户有没有权限连接上来：
1.你从哪里来，host
2.你是谁，user
3.你的密码

用户的这3个信息存储在mysql数据库的user表下

mysql> use mysql
mysql> desc user;
mysql> select Host,User from user;
+-----------+---------------+
| Host      | User          |
+-----------+---------------+
| localhost | mysql.session |       mysql.session用户必须从localhost连接
| localhost | mysql.sys     |        mysql.sys用户必须从localhost连接
| localhost | root          |        root用户必须从localhost连接
+-----------+---------------+
就算知道用户名和密码，但是可以限制ip。

修改user的host域，
update user set host="192.168.1.101" where user='root';
flush privileges;  冲刷权限，

如何修改用户的密码：
update user set password=passwiord('') where user='root'
flush privileges;

mysql库下有一个db表，
用户连上来先通过user表，看能不能进来，然后经过db表判断有没有某个库的操作权，然后通过tables_priv判断有没有库下哪个表的权限。

//新增一个用户，grant[权限1，权限2，权限3......] on 哪个库.哪个表 to 用户@'host' identified by 'password'

常用权限all(所有权限)，creat,drop,insert,delete,update,select

mysql> grant all on *.* to lisi@'127.0.0.1' identified by '';
Query OK, 0 rows affected

mysql> select Host,User from user;
+-----------+---------------+
| Host      | User          |
+-----------+---------------+
| 127.0.0.1 | lisi          |
| localhost | mysql.session |
| localhost | mysql.sys     |
| localhost | root          |
+-----------+---------------+

C:\Users\Administrator>mysql -h127.0.0.1 -ulisi -p   //用户lisi登陆
Enter password: ******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.20 MySQL Community Server (GPL)

mysql> select * from user where user='lisi' \G;
*************************** 1. row ***************************
                  Host: 127.0.0.1
                  User: lisi
           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: *FD571203974BA9AFE270FE62151AE967ECA5E0AA
      password_expired: N
 password_last_changed: 2017-12-29 21:30:25
     password_lifetime: NULL
        account_locked: N
1 row in set (0.00 sec)

//收回权限，revoke all on *.* from lisi@'127.0.0.1',

mysql> revoke all on *.* from lisi@'127.0.0.1';
Query OK, 0 rows affected

mysql> select * from user where user='lisi' \G;
*************************** 1. row ***************************
                  Host: 127.0.0.1
                  User: lisi
           Select_priv: N
           Insert_priv: N
           Update_priv: N
           Delete_priv: N
           Create_priv: N
             Drop_priv: N
           Reload_priv: N
         Shutdown_priv: N
          Process_priv: N
             File_priv: N
            Grant_priv: N
       References_priv: N
            Index_priv: N
            Alter_priv: N
          Show_db_priv: N
            Super_priv: N
 Create_tmp_table_priv: N
      Lock_tables_priv: N
          Execute_priv: N
       Repl_slave_priv: N
      Repl_client_priv: N
      Create_view_priv: N
        Show_view_priv: N
   Create_routine_priv: N
    Alter_routine_priv: N
      Create_user_priv: N
            Event_priv: N
          Trigger_priv: N
Create_tablespace_priv: N
              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: *FD571203974BA9AFE270FE62151AE967ECA5E0AA
      password_expired: N
 password_last_changed: 2017-12-29 21:30:25
     password_lifetime: NULL
        account_locked: N
1 row in set (0.00 sec)

mysql库下面的user里面可以检测能不能登陆，并且里面的权限是全局的，所有库所有表的。

//不是全局授权，而是分库分表管理权限。
grant all on test3.* to lidi@'127.0.0.1';  //给lisi test3库所有表的所有权限。
//针对某个表做授权
grant creat,drop,insert,update,select on test3.goods to lisi@'127.0.0.1';//test3库的goods表做权限控制，

//数据库级别的权限在db表中，表级别的权限在tables_priv表中。
mysql> select * from db \G;  //哪个用户在哪个库哪个主机有哪些权限
*************************** 1. row ***************************
                 Host: localhost
                   Db: performance_schema
                 User: mysql.session
          Select_priv: Y
          Insert_priv: N
          Update_priv: N
          Delete_priv: N
          Create_priv: N
            Drop_priv: N
           Grant_priv: N
      References_priv: N
           Index_priv: N
           Alter_priv: N
Create_tmp_table_priv: N
     Lock_tables_priv: N
     Create_view_priv: N
       Show_view_priv: N
  Create_routine_priv: N
   Alter_routine_priv: N
         Execute_priv: N
           Event_priv: N
         Trigger_priv: N
*************************** 2. row ***************************
                 Host: localhost
                   Db: sys
                 User: mysql.sys
          Select_priv: N
          Insert_priv: N
          Update_priv: N
          Delete_priv: N
          Create_priv: N
            Drop_priv: N
           Grant_priv: N
      References_priv: N
           Index_priv: N
           Alter_priv: N
Create_tmp_table_priv: N
     Lock_tables_priv: N
     Create_view_priv: N
       Show_view_priv: N
  Create_routine_priv: N
   Alter_routine_priv: N
         Execute_priv: N
           Event_priv: N
         Trigger_priv: Y
*************************** 4. row ***************************
                 Host: 127.0.0.1
                   Db: test2
                 User: lisi
          Select_priv: Y
          Insert_priv: Y
          Update_priv: Y
          Delete_priv: Y
          Create_priv: Y
            Drop_priv: Y
           Grant_priv: N
      References_priv: Y
           Index_priv: Y
           Alter_priv: Y
Create_tmp_table_priv: Y
     Lock_tables_priv: Y
     Create_view_priv: Y
       Show_view_priv: Y
  Create_routine_priv: Y
   Alter_routine_priv: Y
         Execute_priv: Y
           Event_priv: Y
         Trigger_priv: Y
4 rows in set (0.00 sec)

mysql> select * from tables_priv \G;
*************************** 1. row ***************************
       Host: localhost
         Db: mysql
       User: mysql.session
 Table_name: user
    Grantor: boot@connecting host
  Timestamp: 0000-00-00 00:00:00
 Table_priv: Select
Column_priv:
*************************** 2. row ***************************
       Host: localhost
         Db: sys
       User: mysql.sys
 Table_name: sys_config
    Grantor: root@localhost
  Timestamp: 2017-12-25 15:09:21
 Table_priv: Select
Column_priv:
*************************** 3. row ***************************
       Host: 127.0.0.1
         Db: test3
       User: lisi
 Table_name: goods
    Grantor: root@localhost
  Timestamp: 0000-00-00 00:00:00
 Table_priv: Select,Insert,Update,Create,Drop
Column_priv:
3 rows in set (0.00 sec)

//mysql的权限控制可以精确到列，常用的授权项，