What should I do if I fail to connect to the database using php?

Solution to failure to connect to the database using php: 1. Open the php.ini configuration file, remove the comment semicolon in front of "extension=php_mysql.dll", and specify the absolute path of "php_mysql.dll" through extension ; 2. Modify the my.ini configuration file of mysql; 3. Modify the data set character set.

The operating environment of this tutorial: Windows 10 system, PHP version 8.1, Dell G3 computer.

What should I do if I fail to connect to the database using PHP?

Pit pits encountered by PHP connecting to mysql (with solutions, personal test is valid)

Pit pits encountered by PHP connecting mysql

Environment: win10 PHP5.48 Apache2.2 Mysql8.017

PHP connection instance

<?php     $link = mysql_connect("localhost", "myuser", "mypasswd");
    #myuser: 用户名    #mypasswd： 密码    var_dump($link);
    mysql_close();?>

Pit 1 Call to undefined function mysql_connect()

Cause: mysql_connect() function is not defined and is not enabled in the php.ini configuration file

Solution:

1.1 Configure php.ini function

##1.1.1 Remove the comment semicolon in front of extension=php_mysql.dll;

1.1.2 Specify the absolute path of php_mysql.dll through extension

1.2 Configuration file path

1.2.1 Copy the php.ini file to c:\windows\system32

1.3 Restart the Apache service (I won’t say how to restart it specifically, if you don’t know this, then This article will not help you)

Pit 2 The server requested authentication method unknown to the client

Reason: Caused by the inconsistency of the password lock mechanism of mysql8. .

Solution

1.1 Modify the my.ini configuration file of mysql

1.2 View the corresponding user authentication plug-in in mysql

If the authentication method has not changed, perform the following operations

# 登陆mysqlmysql -uroot -p# 使用mysql数据库use mysql;# 修改身份验证插件ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '你的密码';

坑3  字符集错误 sever sent charset unknowd to the client ,Please report to the decelopers

原因： MySQL8更换了默认的服务器字符集，mysql8.x的字符集character-set-server默认是utf8mb4，不再是5.x时代的utf8了

解决方法：

修改mysql的my.ini配置文件，具体修改条目如下：(这里只展示了需要修改的条目，原配置文件内容很多)

[client]default-character-set=utf8[mysql]default-character-set=utf8[mysqld]collation-server = utf8_unicode_cicharacter-set-server = utf8

切记：任何每一次的修改，都需要重启Apache服务，以及mysql服务!!!

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