PHP未定义变量mysqli连接 [英] PHP undefined variable mysqli connection

问题描述

我有一个mysql连接，该连接包含在一个单独的文件中:

I have a mysql connection which is included in a separate file:

require 'settings.php';

我有一个包含所有功能的文件，还包括:

and I have a file with all functions, also included:

require 'functions.php';

在设置中看起来像这样:

In the settings there it looks like this:

$db = mysqli_connect("host", "username", "passwort", "database");
    if(!$db) {
        exit("Error: ".mysqli_connect_error());
    }

和一个函数使用这种连接，如下所示:

and a function uses this connection like this:

function includehomepage() {
            $data = array();
            $query = "SELECT pagecontent FROM `pages` WHERE `id` = `0`";
            $query = mysqli_query($db, $query);
            $data = mysqli_fetch_assoc($query);
            return $data['pagecontent'];
        }

但是我收到这样的错误消息:

But I get an error message like this:

Undefined variable: db in /var/... on line 18

你有答案吗?该变量必须在包含的文件中定义.感谢您的回答！

Do you have an answer? The variable have to be defined in the included file.. I am confused. Thanks for your answers!

推荐答案

变量范围问题.查看 global

Variable scope problem. Look at global

function includehomepage() {
   global $db;
   $data = array();
   $query = "SELECT pagecontent FROM `pages` WHERE `id` = '0'";
   $query = mysqli_query($db, $query);
   $data = mysqli_fetch_assoc($query);
   return $data['pagecontent'];
}

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