解决修改root密码链接不上mysql数据库|解决修改root密码链接不上mysql数据库

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自己又随便写了个test.php链接数据库测试，结果显示： Could not 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 说明不是，配置文件的问题，是修改密码的问题，把如上问题放到百度： 1. Change MySQL to NOT to use old_passwords It seems that even MySQL 5.x versions still default to the old password hashes. You need to change this in “my.cnf” (e.g. /etc/my.cnf): remove or comment out the line that says

	  
		 代码如下
		
	  
	  
		
old_passwords = 1
//old_passwords = 1为16位
//所以这里要先
//SET old_passwords = 0;
//这样使新密码的长度也变成41位

	  
	Restart MySQL. If you don’t, MySQL will keep using the old password format, which will mean that you cannot upgrade the passwords using the builtin PASSWORD() hashing function. You can test this by running:

	  
		 代码如下
		
	  
	  
		
mysql> SELECT Length(PASSWORD("xyz"));

	  
	结果如下图：很明显16位

The old password hashes are 16 characters, the new ones are 41 characters.

2. Change the format of all the passwords in the database to the new format Connect to the database, and run the following query:

	  
		 代码如下
		
	  
	  
		
mysql> SELECT user, Length(`Password`) FROM `mysql`.`user`;

	  
	This will show you which passwords are in the old format, ex:

如图： Notice here that each user can have multiple rows (one for each different host specification). To update the password for each user, run the following:

	  
		 代码如下
		
	  
	  
		
UPDATE mysql.user SET Password = PASSWORD("password") WHERE user = "username";

	  
	如图：

Finally, flush privileges:

	  
		 代码如下
		
	  
	  
		
FLUSH PRIVILEGES;

	  
	最后再查询一下

	  
		 代码如下
		
	  
	  
		
mysql> SELECT user, Length(`Password`) FROM `mysql`.`user`;

	  
	结果如下图：（变成41位了，成功）

成功后退出exit

最后重新启动一下mysql

	  
		 代码如下
		
	  
	  
		
service mysqld restart

	  
	ok

 

 代码如下 mysql>
SET old_passwords = 0;
UPDATE mysql.user SET Password = PASSWORD("testpass") WHERE User = "testuser" limit 1; 
SELECT LENGTH(Password) FROM mysql.user WHERE User = "testuser"; 
FLUSH PRIVILEGES;

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