Access Granted - The Mechanics (
Page 7 of 7 )
Now that you know how the
grant tables work, the final item on the agenda is the mechanics of implementing
changes to the tables. MySQL offers two methods of altering access rights in the
grant tables - you can either use INSERT, UPDATE and DELETE queries to alter the
information in the tables, or use the GRANT and REVOKE
commands.
Personally, I prefer the former, since it's much easier to
understand and remember - although typing in long-winded SQL queries is
sometimes a little tedious. Power users would do well to learn GRANT and REVOKE
command syntax - details are available in the mySQL manual. For the moment, I'll
simply take you through a couple of examples, using both methods, so that you
have some insight into the differences between the two methods.
The first
example sets up a user "tom", password "tommygun", who has permission to access
the "recipes" database only from "localhost"
mysql> INSERT INTO user (Host, User, Password)
VALUES('localhost','tom',PASSWORD('tommygun'));
mysql> INSERT INTO db (Host, Db, User, Select_priv, Insert_priv,
Update_priv, Delete_priv, Create_priv, Drop_priv) VALUES
('localhost','recipes','tom','Y','Y','Y','Y','N','N');
The equivalent GRANT command is:
mysql> GRANT SELECT, INSERT, UPDATE, DELETE, ON recipes.* TO tom@localhost
IDENTIFIED BY 'tommygun';
You could set up an equivalent of the "root" user
with
mysql> GRANT ALL PRIVILEGES ON *.* TO god@localhost IDENTIFIED BY 'master';
or
mysql> INSERT INTO user (Host, User, Password, Select_priv, Insert_priv,
Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv,
Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv,
Index_priv, Alter_priv) VALUES ('localhost', 'god', PASSWORD('master'),
'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y')
It should be noted that privileges set using GRANT and
REVOKE are immediately activated; however, privileges set via regular SQL
queries require a server reload to come into effect. A server reload can be
accomplished via the "mysqladmin" command
$ mysqladmin reload
or with the
mysql> FLUSH PRIVILEGES;
command.
And that's about it. I hope you find this
information useful, and that you can use it when maintaining your own databases.
Ciao!
