Codeigniter: fatal error call to undefined functio

问题:

I just changed my server and experience these errors below:

Fatal error: Call to undefined function mysqli_init() in /home/blacktwitter/public_html/system/database/drivers/mysqli/mysqli_driver.php on line 126
A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at /home/blacktwitter/public_html/system/database/drivers/mysqli/mysqli_driver.php:126)

Filename: core/Common.php

Line Number: 564

Backtrace:

A PHP Error was encountered

Severity: Error

Message: Call to undefined function mysqli_init()

Filename: mysqli/mysqli_driver.php

Line Number: 126

Backtrace:

Website is in Codeigniter. It works on one server very well and on the local machine too. But when I upload that website at the new server I have that errors. Of course I changed important parameters like database connection, base_url() etc.

I was suspicious about database, but I have created a new database and user etc. and changed connection info.

Why does this happen? It will be helpful to know if it is a bug at the server or at the website. Also when I create some index.html with some test code everything is fine.

回答1:

It is not a bug in your application, it is just a missing driver, so, you have couple of options...

Go to your php init and uncomment the following:

extension=php_mysqli.dll

If not, try installing it at your server, it varies depending on your distribution.

Try installing php5-mysqlnd

If you cannot do it by hosting restrictions then just move to mysql driver (wont need to change other configurations or queries in CodeIgniter or anything else...)

like this (at your config file)

$db['default']['dbdriver'] = 'mysql'; (you might have mysqli now)

回答2:

I just had this issue on a ubuntu16.04, php7.1 install with Codeigniter 3.

Solution was simple (if hard to find!)

sudo apt-get install php7.0-mysql

I realised that the mysql*.ini files where missing from the etc/php/7.1/mods-available directory. Not sure how it happened, but that worked for me.

If you use 7.2, simply type sudo apt-get install php7.2-mysql

回答3:

This is actually not a CodeIgniter issue but PHP installation issue.

I have installed PHP5.6 in my Linux server and is having a hard time following the googled solutions of using the ff command in order to install the missing mysqli_extension in PHP.

What I tried is but is returning the warning message: Unable to locate package php5-mysqli

sudo apt-get install php5-mysqli

However, my php version is 5.6 so I tried

sudo apt-get install php5.6-mysqli

Then it works.

回答4:

Open the folder where you have installed PHP, Edit php.ini file
uncomment this line: extension=php_mysqli.dll

回答5:

For me this was a missing line in php.ini that solved it, as I copied another php.ini file to my XAMPP installation. Worth checking if the line: "extension=php_mysqli.dll" exist (if running Windows, but this isn't applicable for OP, as it's a Linux system), or if the "extension_dir" exists and is correct.

回答6:

1、apt-get install (yum, compile install whatever) php5-mysqlnd extension.

2、if not work, make sure mysqli is loaded

    root@x19-ws07-1:/etc/php5/apache2# cat /proc/31682/maps | grep mysql

if is loaded, you can see:

    7f2cd3266000-7f2cd3285000 r-xp 00000000 fd:00 864561                     /usr/lib/php5/20131226/mysqli.so
    7f2cd69ef000-7f2cd6a2e000 r-xp 00000000 fd:00 864559                     /usr/lib/php5/20131226/mysqlnd.so

3、if not loaded use php --ini to find config file

    xxxx@xxxx:~$ php --ini
    Configuration File (php.ini) Path: /etc/php5/apache2
    Loaded Configuration File:         /etc/php5/apache2/php.ini
    Scan for additional .ini files in: /etc/php5/apache2/conf.d
    Additional .ini files parsed:      /etc/php5/apache2/conf.d/05-opcache.ini,
    /etc/php5/apache2/conf.d/20-mysqli.ini

4、if not config extension, config like this and remember restart your web server

    xxxx@xxxxx:~$ cat /etc/php5/apache2/conf.d/20-mysqli.ini
    ; configuration for php MySQL module
    ; priority=20
    extension=mysqli.so

回答7:

In Linux, you can install MySQL driver extension.

sudo apt-get install php-mysql

In Windows with XAMPP, the driver has already saved in ext directory, but you need to enable it in php.ini. You need to uncomment this line:

extension=php_mysqli.dll

You also need to check the extension directory location in php.ini. I use absolute path (not relative path) declaration to make it works.

extension_dir="your\absolute\path\to\xampp\php\ext"

For example,

extension_dir="C:\xampp\php\ext"

回答8:

I tried, comment out below line in /etc/php/cli/php.ini file.

extension=php_mysqli.dll

I am using Ubuntu 16.04 on AWS-EC2 instances and PHP 7.0. This solved my problem.

回答9:

Use this:

sudo apt-get install php7.*-mysqli

or

sudo phpenmod mysqli
sudo service apache2 restart

回答10:

If your webserver is running with a lower version of MySQL, then you will get this error as MySQLi is not supported in MySQL < 4.1.3

It is highly recommended to go with MySQLi instead of going back to MySQL extension.

More info on php.net

回答11:

I suggest you do the following:

change:

'dbdriver' => 'mysqli',
'dbprefix' => '',

to:

'dbdriver' => 'mysql',
'dbprefix' => '',

in database.php file.