A root account password can be set several ways. The following discussion demonstrates three methods:
Use the SET PASSWORD statement
Use the UPDATE statement
Use the mysqladmin command-line client program
法一：
shell> mysql -u root
mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('new_password');
mysql> SET PASSWORD FOR 'root'@'127.0.0.1' = PASSWORD('new_password');
mysql> SET PASSWORD FOR 'root'@'::1' = PASSWORD('new_password');
mysql> SET PASSWORD FOR 'root'@'host_name' = PASSWORD('new_password');
You can also use a single statement that assigns a password to all root accounts by using UPDATE to modify the mysql.user table directly. This method works on any platform:
法二：
shell> mysql -u root
mysql> UPDATE mysql.user SET Password = PASSWORD('new_password')
-> WHERE User = 'root';
mysql> FLUSH PRIVILEGES;
The FLUSH statement causes the server to reread the grant tables. Without it, the password change remains unnoticed by the server until you restart it.
法三：
To assign passwords to the root accounts using mysqladmin, execute the following commands:
shell> mysqladmin -u root password "new_password"
shell> mysqladmin -u root -h host_name password "new_password"
Those commands apply both to Windows and to Unix. The double quotation marks around the password are not always necessary, but you should use them if the password contains spaces or other characters that are special to your command interpreter.
The mysqladmin method of setting the root account passwords does not work for the 'root'@'127.0.0.1' or 'root'@'::1' account. Use the SET PASSWORD method shown earlier.
After the root passwords have been set, you must supply the appropriate password whenever you connect as root to the server. For example, to shut down the server with mysqladmin, use this command:
shell> mysqladmin -u root -p shutdown
Enter password: (enter root password here)
The mysql commands in the following instructions include a -p option based on the assumption that you have assigned the root account passwords using the preceding instructions and must specify that password when connecting to the server.
Assigning Anonymous Account Passwords
To assign passwords to the anonymous accounts, connect to the server as root, then use either SET PASSWORD or UPDATE.
To use SET PASSWORD on Windows, do this:
shell> mysql -u root -p
Enter password: (enter root password here)
mysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('new_password');
To use SET PASSWORD on Unix, do this:
shell> mysql -u root -p
Enter password: (enter root password here)
mysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('new_password');
mysql> SET PASSWORD FOR ''@'host_name' = PASSWORD('new_password');
To set the anonymous-user account passwords with a single UPDATE statement, do this (on any platform):
shell> mysql -u root -p
Enter password: (enter root password here)
mysql> UPDATE mysql.user SET Password = PASSWORD('new_password')
-> WHERE User = '';
mysql> FLUSH PRIVILEGES;
The FLUSH statement causes the server to reread the grant tables. Without it, the password change remains unnoticed by the server until you restart it.
Removing Anonymous Accounts
If you prefer to remove any anonymous accounts rather than assigning them passwords, do so as follows on Windows:
shell> mysql -u root -p
Enter password: (enter root password here)
mysql> DROP USER ''@'localhost';
On Unix, remove the anonymous accounts like this:
shell> mysql -u root -p
Enter password: (enter root password here)
mysql> DROP USER ''@'localhost';
mysql> DROP USER ''@'host_name';
Securing Test Databases
By default, the mysql.db table contains rows that permit access by any user to the test database and other databases with names that start with test_. (These rows have an empty User column value, which for access-checking purposes matches any user name.) This means that such databases can be used even by accounts that otherwise possess no privileges. If you want to remove any-user access to test databases, do so as follows:
shell> mysql -u root -p
Enter password: (enter root password here)
mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%';
mysql> FLUSH PRIVILEGES;
The FLUSH statement causes the server to reread the grant tables. Without it, the privilege change remains unnoticed by the server until you restart it.
With the preceding change, only users who have global database privileges or privileges granted explicitly for the test database can use it. However, if you prefer that the database not exist at all, drop it:
mysql> DROP DATABASE test;
