I'm creating a bash script which, among other things, gathers some data from a MySQL database. My MySQL user has write privileges, but for safety reasons I would like to temporarily set it to a read only state. Is it possible to do this from a command line?
To answer your original question, you can put your whole database to read only mode by this commands:
FLUSH TABLES WITH READ LOCK;
SET GLOBAL read_only = 1;
and back to normal mode with:
SET GLOBAL read_only = 0;
UNLOCK TABLES;
Beware that this is an operation which will have deep impact on the behavior of the database. So before executing this, read the available documentation to the commands above. A much more common way is to revoke DML privileges from the specific user and afterwards grant them back.
If you're using MySQL 5.6 or newer and InnoDB, you can make a session read-only.
SET SESSION TRANSACTION READ ONLY;
https://dev.mysql.com/doc/refman/5.6/en/set-transaction.html
"READ ONLY" also offers a modest performance benefit.
Well, if the user right now has all privileges first, you need to revoke it
$>mysql -u DB_USER -pDB_PASS --execute="REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'YOUR_USER';"
After that you give him, the select permission
$>mysql -u DB_USER -pDB_PASS --execute="GRANT SELECT ON 'YOUR_DATABASE'@.* TO 'YOUR_USER'@'%';FLUSH PRIVILEGES;"
Do your stuff and after that grant privileges again to the user
$>mysql -u DB_USER -pDB_PASS --execute="GRANT ALL ON 'YOUR_DATABASE'@.* TO 'YOUR_USER'@'%';FLUSH PRIVILEGES;"
And that's all folks
NOTE: Review for quotation, perhaps i forgot something
来源：https://stackoverflow.com/questions/18401120/how-do-i-set-mysql-temporarily-to-read-only-through-the-command-line