MySQL provides privileges that apply in different contexts and at different levels of operation:
Administrative privileges enable users to manage operation of the MySQL server. These privileges are global because they are not specific to a particular database.
Database privileges apply to a database and to all objects within it. These privileges can be granted for specific databases, or globally so that they apply to all databases.
Privileges for database objects such as tables, indexes, views, and stored routines can be granted for specific objects within a database, for all objects of a given type within a database (for example, all tables in a database), or globally for all objects of a given type in all databases).
Information about account privileges is stored in the
user
, db
,
host
, tables_priv
,
columns_priv
, and procs_priv
tables in the mysql
database (see
Section 5.4.2, “Privilege System Grant Tables”). The MySQL server reads
the contents of these tables into memory when it starts and
reloads them under the circumstances indicated in
Section 5.4.6, “When Privilege Changes Take Effect”. Access-control decisions are
based on the in-memory copies of the grant tables.
Some releases of MySQL introduce changes to the structure of the grant tables to add new access privileges or features. Whenever you update to a new version of MySQL, you should update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See Section 4.4.7, “mysql_upgrade — Check Tables for MySQL Upgrade”.
The following table shows the privilege names used at the SQL
level in the GRANT
and
REVOKE
statements, along with the
column name associated with each privilege in the grant tables and
the context in which the privilege applies.
Table 5.6. Permissible Privileges for GRANT
and
REVOKE
Privilege | Column | Context |
---|---|---|
CREATE | Create_priv | databases, tables, or indexes |
DROP | Drop_priv | databases, tables, or views |
GRANT OPTION | Grant_priv | databases, tables, or stored routines |
REFERENCES | References_priv | databases or tables |
EVENT | Event_priv | databases |
ALTER | Alter_priv | tables |
DELETE | Delete_priv | tables |
INDEX | Index_priv | tables |
INSERT | Insert_priv | tables or columns |
SELECT | Select_priv | tables or columns |
UPDATE | Update_priv | tables or columns |
CREATE TEMPORARY TABLES | Create_tmp_table_priv | tables |
LOCK TABLES | Lock_tables_priv | tables |
TRIGGER | Trigger_priv | tables |
CREATE VIEW | Create_view_priv | views |
SHOW VIEW | Show_view_priv | views |
ALTER ROUTINE | Alter_routine_priv | stored routines |
CREATE ROUTINE | Create_routine_priv | stored routines |
EXECUTE | Execute_priv | stored routines |
FILE | File_priv | file access on server host |
CREATE TABLESPACE | Create_tablespace_priv | server administration |
CREATE USER | Create_user_priv | server administration |
PROCESS | Process_priv | server administration |
RELOAD | Reload_priv | server administration |
REPLICATION CLIENT | Repl_client_priv | server administration |
REPLICATION SLAVE | Repl_slave_priv | server administration |
SHOW DATABASES | Show_db_priv | server administration |
SHUTDOWN | Shutdown_priv | server administration |
SUPER | Super_priv | server administration |
ALL [PRIVILEGES] | server administration | |
USAGE | server administration |
The following list provides a general description of each privilege available in MySQL. Particular SQL statements might have more specific privilege requirements than indicated here. If so, the description for the statement in question provides the details.
The
ALL
orALL PRIVILEGES
privilege specifier is shorthand. It stands for “all privileges available at a given privilege level” (exceptGRANT OPTION
). For example, grantingALL
at the global or table level grants all global privileges or all table-level privileges.The
ALTER
privilege enables use ofALTER TABLE
to change the structure of or rename tables. (ALTER TABLE
also requires theINSERT
andCREATE
privileges.)The
ALTER ROUTINE
privilege is needed to alter or drop stored routines (procedures and functions).The
CREATE
privilege enables creation of new databases and tables.The
CREATE ROUTINE
privilege is needed to create stored routines (procedures and functions).The
CREATE TABLESPACE
privilege is needed to create, alter, or drop tablespaces and log file groups.The
CREATE TEMPORARY TABLES
privilege enables the use of the keywordTEMPORARY
inCREATE TABLE
statements.The
CREATE USER
privilege enables use ofCREATE USER
,DROP USER
,RENAME USER
, andREVOKE ALL PRIVILEGES
.The
CREATE VIEW
privilege enables use ofCREATE VIEW
.The
DELETE
privilege enables rows to be deleted from tables in a database.The
DROP
privilege enables you to drop (remove) existing databases, tables, and views. TheDROP
privilege is required in order to use the statementALTER TABLE ... DROP PARTITION
on a partitioned table. TheDROP
privilege is also required forTRUNCATE TABLE
. If you grant theDROP
privilege for themysql
database to a user, that user can drop the database in which the MySQL access privileges are stored.The
EVENT
privilege is required to create, alter, or drop events for the Event Scheduler.The
EXECUTE
privilege is required to execute stored routines (procedures and functions).The
FILE
privilege gives you permission to read and write files on the server host using theLOAD DATA INFILE
andSELECT ... INTO OUTFILE
statements and theLOAD_FILE()
function. A user who has theFILE
privilege can read any file on the server host that is either world-readable or readable by the MySQL server. (This implies the user can read any file in any database directory, because the server can access any of those files.) TheFILE
privilege also enables the user to create new files in any directory where the MySQL server has write access. As a security measure, the server will not overwrite existing files.The
GRANT OPTION
privilege enables you to give to other users or remove from other users those privileges that you yourself possess.The
INDEX
privilege enables you to create or drop (remove) indexes.INDEX
applies to existing tables. If you have theCREATE
privilege for a table, you can include index definitions in theCREATE TABLE
statement.The
INSERT
privilege enables rows to be inserted into tables in a database.INSERT
is also required for theANALYZE TABLE
,OPTIMIZE TABLE
, andREPAIR TABLE
table-maintenance statements.The
LOCK TABLES
privilege enables the use of explicitLOCK TABLES
statements to lock tables for which you have theSELECT
privilege. This includes the use of write locks, which prevents other sessions from reading the locked table.The
PROCESS
privilege pertains to display of information about the threads executing within the server (that is, information about the statements being executed by sessions). The privilege enables use ofSHOW PROCESSLIST
or mysqladmin processlist to see threads belonging to other accounts; you can always see your own threads.The
PROXY
privilege enables a user to impersonate or become known as another user. See Section 5.5.7, “Proxy Users”. This privilege was added in MySQL 5.5.7.The
REFERENCES
privilege currently is unused.The
RELOAD
privilege enables use of theFLUSH
statement. It also enables mysqladmin commands that are equivalent toFLUSH
operations:flush-hosts
,flush-logs
,flush-privileges
,flush-status
,flush-tables
,flush-threads
,refresh
, andreload
.The
reload
command tells the server to reload the grant tables into memory.flush-privileges
is a synonym forreload
. Therefresh
command closes and reopens the log files and flushes all tables. The otherflush-
commands perform functions similar toxxx
refresh
, but are more specific and may be preferable in some instances. For example, if you want to flush just the log files,flush-logs
is a better choice thanrefresh
.The
REPLICATION CLIENT
privilege enables the use ofSHOW MASTER STATUS
andSHOW SLAVE STATUS
.The
REPLICATION SLAVE
privilege should be granted to accounts that are used by slave servers to connect to the current server as their master. Without this privilege, the slave cannot request updates that have been made to databases on the master server.The
SELECT
privilege enables you to select rows from tables in a database.SELECT
statements require theSELECT
privilege only if they actually retrieve rows from a table. SomeSELECT
statements do not access tables and can be executed without permission for any database. For example, you can useSELECT
as a simple calculator to evaluate expressions that make no reference to tables:SELECT 1+1; SELECT PI()*2;
The
SELECT
privilege is also needed for other statements that read column values. For example,SELECT
is needed for columns referenced on the right hand side ofcol_name
=expr
assignment inUPDATE
statements or for columns named in theWHERE
clause ofDELETE
orUPDATE
statements.The
SHOW DATABASES
privilege enables the account to see database names by issuing theSHOW DATABASE
statement. Accounts that do not have this privilege see only databases for which they have some privileges, and cannot use the statement at all if the server was started with the--skip-show-database
option. Note that any global privilege is a privilege for the database.The
SHOW VIEW
privilege enables use ofSHOW CREATE VIEW
.The
SHUTDOWN
privilege enables use of the mysqladmin shutdown command. There is no corresponding SQL statement.The
SUPER
privilege enables an account to useCHANGE MASTER TO
,KILL
or mysqladmin kill to kill threads belonging to other accounts (you can always kill your own threads),PURGE BINARY LOGS
, configuration changes usingSET GLOBAL
to modify global system variables, the mysqladmin debug command, enabling or disabling logging, performing updates even if theread_only
system variable is enabled, starting and stopping replication on slave servers, specification of any account in theDEFINER
attribute of stored programs and views, and enables you to connect (once) even if the connection limit controlled by themax_connections
system variable is reached.To create or alter stored functions if binary logging is enabled, you may also need the
SUPER
privilege, as described in Section 19.7, “Binary Logging of Stored Programs”.The
TRIGGER
privilege enables trigger operations. You must have this privilege for a table to create, drop, or execute triggers for that table.The
UPDATE
privilege enables rows to be updated in tables in a database.The
USAGE
privilege specifier stands for “no privileges.” It is used at the global level withGRANT
to modify account attributes such as resource limits or SSL characteristics without affecting existing account privileges.
It is a good idea to grant to an account only those privileges
that it needs. You should exercise particular caution in granting
the FILE
and administrative
privileges:
The
FILE
privilege can be abused to read into a database table any files that the MySQL server can read on the server host. This includes all world-readable files and files in the server's data directory. The table can then be accessed usingSELECT
to transfer its contents to the client host.The
GRANT OPTION
privilege enables users to give their privileges to other users. Two users that have different privileges and with theGRANT OPTION
privilege are able to combine privileges.The
ALTER
privilege may be used to subvert the privilege system by renaming tables.The
SHUTDOWN
privilege can be abused to deny service to other users entirely by terminating the server.The
PROCESS
privilege can be used to view the plain text of currently executing statements, including statements that set or change passwords.The
SUPER
privilege can be used to terminate other sessions or change how the server operates.Privileges granted for the
mysql
database itself can be used to change passwords and other access privilege information. Passwords are stored encrypted, so a malicious user cannot simply read them to know the plain text password. However, a user with write access to theuser
tablePassword
column can change an account's password, and then connect to the MySQL server using that account.