目录
user : 表示用户名,同一用户通过不同方式链接的权限是不一样的。
MySQL服务器通过权限表来控制用户对数据库的访问,权限表存在在mysql数据库中。这些权限表是最重要的是`user` `db` `tables_priv` `columns_priv` `procs_priv`等。在MySQL启动时,服务器将这些数据表中的权限信息读入内存。
上文中提到的mysql数据库是:
进去看看:
use mysql;
show tables;
user表是MySQL中最重要的一个权限表, 记录用户账号和权限信息 :
desc user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+| Field | Type | Null | Key | Default | Extra |+------------------------+-----------------------------------+------+-----+-----------------------+-------+| Host | char(60) | NO | PRI | | || User | char(32) | NO | PRI | | || Select_priv | enum('N','Y') | NO | | N | || Insert_priv | enum('N','Y') | NO | | N | || Update_priv | enum('N','Y') | NO | | N | || Delete_priv | enum('N','Y') | NO | | N | || Create_priv | enum('N','Y') | NO | | N | || Drop_priv | enum('N','Y') | NO | | N | || Reload_priv | enum('N','Y') | NO | | N | || Shutdown_priv | enum('N','Y') | NO | | N | || Process_priv | enum('N','Y') | NO | | N | || File_priv | enum('N','Y') | NO | | N | || Grant_priv | enum('N','Y') | NO | | N | || References_priv | enum('N','Y') | NO | | N | || Index_priv | enum('N','Y') | NO | | N | || Alter_priv | enum('N','Y') | NO | | N | || Show_db_priv | enum('N','Y') | NO | | N | || Super_priv | enum('N','Y') | NO | | N | || Create_tmp_table_priv | enum('N','Y') | NO | | N | || Lock_tables_priv | enum('N','Y') | NO | | N | || Execute_priv | enum('N','Y') | NO | | N | || Repl_slave_priv | enum('N','Y') | NO | | N | || Repl_client_priv | enum('N','Y') | NO | | N | || Create_view_priv | enum('N','Y') | NO | | N | || Show_view_priv | enum('N','Y') | NO | | N | || Create_routine_priv | enum('N','Y') | NO | | N | || Alter_routine_priv | enum('N','Y') | NO | | N | || Create_user_priv | enum('N','Y') | NO | | N | || Event_priv | enum('N','Y') | NO | | N | || Trigger_priv | enum('N','Y') | NO | | N | || Create_tablespace_priv | enum('N','Y') | NO | | N | || ssl_type | enum('','ANY','X509','SPECIFIED') | NO | | | || ssl_cipher | blob | NO | | NULL | || x509_issuer | blob | NO | | NULL | || x509_subject | blob | NO | | NULL | || max_questions | int(11) unsigned | NO | | 0 | || max_updates | int(11) unsigned | NO | | 0 | || max_connections | int(11) unsigned | NO | | 0 | || max_user_connections | int(11) unsigned | NO | | 0 | || plugin | char(64) | NO | | mysql_native_password | || authentication_string | text | YES | | NULL | || password_expired | enum('N','Y') | NO | | N | || password_last_changed | timestamp | YES | | NULL | || password_lifetime | smallint(5) unsigned | YES | | NULL | || account_locked | enum('N','Y') | NO | | N | |+------------------------+-----------------------------------+------+-----+-----------------------+-------+
这些字段可以分成4类,分别是范围列(或用户列)、权限列、安全列和资源控制列。
% 表示所有远程通过 TCP方式的连接
IP 地址 如 (192.168.1.2、127.0.0.1) 通过制定ip地址进行的TCP方式的连接
机器名 通过制定网络中的机器名进行的TCP方式的连接
::1 IPv6的本地ip地址,等同于IPv4的 127.0.0.1
localhost 本地方式通过命令行方式的连接 ,比如mysql -u xxx -p xxx 方式的连接
所有密码串通过 password(明文字符串) 生成的密文字符串。MySQL 8.0 在用户管理方面增加了角色管理,默认的密码加密方式也做了调整,由之前的 SHA1 改为了 SHA2 不可逆 。同时加上MySQL 5.7的禁用用户和用户过期的功能,MySQL 在用户管理方面的功能和安全性都较之前版本大大的增强了。
mysql 5.7及之后版本的密码保存到 authentication_string 字段中不再使用password字段。
表示是否拥有GRANT权限
表示是否拥有停止MySQL服务的权限
表示是否拥有超级权限
表示是否拥有EXECUTE权限。拥有EXECUTE权限,可以执行存储过程和函数
为该用户所拥有的权限
安全列只有6个字段,其中两个是ssl相关的(ssl_type、ssl_cipher),用于加密;两个是x509相关的 (x509_issuer、x509_subject) ,用于标识用户;另外两个Plugin字段用于验证用户身份的插件, 该字段不能为空。如果该字段为空,服务器就使用内建授权验证机制验证用户身份。
资源控制列的字段用来 限制用户使用的资源 ,包含4个字段,分别为:
max_questions ,用户每小时允许执行的查询操作次数;
max_updates ,用户每小时允许执行的更新 操作次数;
max_connections ,用户每小时允许执行的连接操作次数;
max_user_connections ,用户 允许同时建立的连接次数。
查看字段:
desc mysql.user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+| Field | Type | Null | Key | Default | Extra |+------------------------+-----------------------------------+------+-----+-----------------------+-------+| Host | char(60) | NO | PRI | | || User | char(32) | NO | PRI | | || Select_priv | enum('N','Y') | NO | | N | || Insert_priv | enum('N','Y') | NO | | N | || Update_priv | enum('N','Y') | NO | | N | || Delete_priv | enum('N','Y') | NO | | N | || Create_priv | enum('N','Y') | NO | | N | || Drop_priv | enum('N','Y') | NO | | N | || Reload_priv | enum('N','Y') | NO | | N | || Shutdown_priv | enum('N','Y') | NO | | N | || Process_priv | enum('N','Y') | NO | | N | || File_priv | enum('N','Y') | NO | | N | || Grant_priv | enum('N','Y') | NO | | N | || References_priv | enum('N','Y') | NO | | N | || Index_priv | enum('N','Y') | NO | | N | || Alter_priv | enum('N','Y') | NO | | N | || Show_db_priv | enum('N','Y') | NO | | N | || Super_priv | enum('N','Y') | NO | | N | || Create_tmp_table_priv | enum('N','Y') | NO | | N | || Lock_tables_priv | enum('N','Y') | NO | | N | || Execute_priv | enum('N','Y') | NO | | N | || Repl_slave_priv | enum('N','Y') | NO | | N | || Repl_client_priv | enum('N','Y') | NO | | N | || Create_view_priv | enum('N','Y') | NO | | N | || Show_view_priv | enum('N','Y') | NO | | N | || Create_routine_priv | enum('N','Y') | NO | | N | || Alter_routine_priv | enum('N','Y') | NO | | N | || Create_user_priv | enum('N','Y') | NO | | N | || Event_priv | enum('N','Y') | NO | | N | || Trigger_priv | enum('N','Y') | NO | | N | || Create_tablespace_priv | enum('N','Y') | NO | | N | || ssl_type | enum('','ANY','X509','SPECIFIED') | NO | | | || ssl_cipher | blob | NO | | NULL | || x509_issuer | blob | NO | | NULL | || x509_subject | blob | NO | | NULL | || max_questions | int(11) unsigned | NO | | 0 | || max_updates | int(11) unsigned | NO | | 0 | || max_connections | int(11) unsigned | NO | | 0 | || max_user_connections | int(11) unsigned | NO | | 0 | || plugin | char(64) | NO | | mysql_native_password | || authentication_string | text | YES | | NULL | || password_expired | enum('N','Y') | NO | | N | || password_last_changed | timestamp | YES | | NULL | || password_lifetime | smallint(5) unsigned | YES | | NULL | || account_locked | enum('N','Y') | NO | | N | |+------------------------+-----------------------------------+------+-----+-----------------------+-------+
查看用户, 以列的方式显示数据:
SELECT * FROM mysql.user \G
*************************** 1. row ***************************Host: %User: rootSelect_priv: YInsert_priv: YUpdate_priv: YDelete_priv: YCreate_priv: YDrop_priv: YReload_priv: YShutdown_priv: YProcess_priv: YFile_priv: YGrant_priv: YReferences_priv: YIndex_priv: YAlter_priv: YShow_db_priv: YSuper_priv: YCreate_tmp_table_priv: YLock_tables_priv: YExecute_priv: YRepl_slave_priv: YRepl_client_priv: YCreate_view_priv: YShow_view_priv: YCreate_routine_priv: YAlter_routine_priv: YCreate_user_priv: YEvent_priv: YTrigger_priv: YCreate_tablespace_priv: Yssl_type:ssl_cipher:x509_issuer:x509_subject:max_questions: 0max_updates: 0max_connections: 0max_user_connections: 0plugin: mysql_native_passwordauthentication_string: *1CBB512647CC0DF0A850C55C13778CEA53552E43password_expired: Npassword_last_changed: 2022-08-24 11:13:22password_lifetime: NULLaccount_locked: N*************************** 2. row ***************************Host: localhostUser: mysql.sessionSelect_priv: NInsert_priv: NUpdate_priv: NDelete_priv: NCreate_priv: NDrop_priv: NReload_priv: NShutdown_priv: NProcess_priv: NFile_priv: NGrant_priv: NReferences_priv: NIndex_priv: NAlter_priv: NShow_db_priv: NSuper_priv: YCreate_tmp_table_priv: NLock_tables_priv: NExecute_priv: NRepl_slave_priv: NRepl_client_priv: NCreate_view_priv: NShow_view_priv: NCreate_routine_priv: NAlter_routine_priv: NCreate_user_priv: NEvent_priv: NTrigger_priv: NCreate_tablespace_priv: Nssl_type:ssl_cipher:x509_issuer:x509_subject:max_questions: 0max_updates: 0max_connections: 0max_user_connections: 0plugin: mysql_native_passwordauthentication_string: *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHEREpassword_expired: Npassword_last_changed: 2022-08-23 15:30:37password_lifetime: NULLaccount_locked: Y*************************** 3. row ***************************Host: localhostUser: mysql.sysSelect_priv: NInsert_priv: NUpdate_priv: NDelete_priv: NCreate_priv: NDrop_priv: NReload_priv: NShutdown_priv: NProcess_priv: NFile_priv: NGrant_priv: NReferences_priv: NIndex_priv: NAlter_priv: NShow_db_priv: NSuper_priv: NCreate_tmp_table_priv: NLock_tables_priv: NExecute_priv: NRepl_slave_priv: NRepl_client_priv: NCreate_view_priv: NShow_view_priv: NCreate_routine_priv: NAlter_routine_priv: NCreate_user_priv: NEvent_priv: NTrigger_priv: NCreate_tablespace_priv: Nssl_type:ssl_cipher:x509_issuer:x509_subject:max_questions: 0max_updates: 0max_connections: 0max_user_connections: 0plugin: mysql_native_passwordauthentication_string: *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHEREpassword_expired: Npassword_last_changed: 2022-08-23 15:30:37password_lifetime: NULLaccount_locked: Y*************************** 4. row ***************************Host: %User: vanSelect_priv: NInsert_priv: NUpdate_priv: NDelete_priv: NCreate_priv: NDrop_priv: NReload_priv: NShutdown_priv: NProcess_priv: NFile_priv: NGrant_priv: NReferences_priv: NIndex_priv: NAlter_priv: NShow_db_priv: NSuper_priv: NCreate_tmp_table_priv: NLock_tables_priv: NExecute_priv: NRepl_slave_priv: NRepl_client_priv: NCreate_view_priv: NShow_view_priv: NCreate_routine_priv: NAlter_routine_priv: NCreate_user_priv: NEvent_priv: NTrigger_priv: NCreate_tablespace_priv: Nssl_type:ssl_cipher:x509_issuer:x509_subject:max_questions: 0max_updates: 0max_connections: 0max_user_connections: 0plugin: mysql_native_passwordauthentication_string: *1CBB512647CC0DF0A850C55C13778CEA53552E43password_expired: Npassword_last_changed: 2022-08-24 11:15:47password_lifetime: NULLaccount_locked: N
查询特定字段:
SELECT host,user,authentication_string,select_priv,insert_priv,drop_privFROM mysql.user;
使用DESCRIBE查看db表的基本结构:
DESCRIBE mysql.db;
+-----------------------+---------------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+-----------------------+---------------+------+-----+---------+-------+| Host | char(60) | NO | PRI | | || Db | char(64) | NO | PRI | | || User | char(32) | NO | PRI | | || Select_priv | enum('N','Y') | NO | | N | || Insert_priv | enum('N','Y') | NO | | N | || Update_priv | enum('N','Y') | NO | | N | || Delete_priv | enum('N','Y') | NO | | N | || Create_priv | enum('N','Y') | NO | | N | || Drop_priv | enum('N','Y') | NO | | N | || Grant_priv | enum('N','Y') | NO | | N | || References_priv | enum('N','Y') | NO | | N | || Index_priv | enum('N','Y') | NO | | N | || Alter_priv | enum('N','Y') | NO | | N | || Create_tmp_table_priv | enum('N','Y') | NO | | N | || Lock_tables_priv | enum('N','Y') | NO | | N | || Create_view_priv | enum('N','Y') | NO | | N | || Show_view_priv | enum('N','Y') | NO | | N | || Create_routine_priv | enum('N','Y') | NO | | N | || Alter_routine_priv | enum('N','Y') | NO | | N | || Execute_priv | enum('N','Y') | NO | | N | || Event_priv | enum('N','Y') | NO | | N | || Trigger_priv | enum('N','Y') | NO | | N | |+-----------------------+---------------+------+-----+---------+-------+
db表用户列有3个字段,分别是 Host 、 User 、 Db 。这3个字段分别表示主机名、用户名和数据库 名。表示从某个主机连接某个用户对某个数据库的操作权限,这3个字段的组合构成了db表的主键。
Create_routine_priv 和 Alter_routine_priv 这两个字段决定用户是否具有创建和修改存储过程的权限。