cannot connect to MySQL 4.1+ using the old insecure authentication.

Warning: mysql_connect(): mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication. Please use an administration tool to reset your password with the command SET PASSWORD = PASSWORD(‘your_existing_password’). This will store a new, and more secure, hash value in mysql.user. If this user is used in other scripts executed by PHP 5.2 or earlier you might need to remove the old-passwords flag from your my.cnf file in Command line code on line 1
mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication. Please use an administration tool to reset your password with the command SET PASSWORD = PASSWORD(‘your_existing_password’). This will store a new, and more secure, hash value in mysql.user. If this user is used in other scripts executed by PHP 5.2 or earlier you might need to remove the old-passwords flag from your my.cnf file

 

SET old_passwords =0;

USE mysql;

UPDATE user SET password =PASSWORD('yourpassword') WHERE user='testuser' limit 1;

SELECT LENGTH(password) FROM user WHERE user='root';

FLUSH PRIVILEGES;

这是困扰我很久了，记下来，方便以后自己出现相同的错误，能及时解决！！！

原文来自：http://www.iforeach.com/archives/608.html