//this is my connection.php
<?php
$pdo = new PDO('mysql:host=localhost;dbname=test;', 'root');
$pdo->exec("SET CHARACTER SET utf8");
?>
//this is my class.php
<?php
include 'connection.php';
$stmt = $pdo->prepare(query here); //wrong part
?>
problem: Error undefined $pdo, what is the right way in doing this? But when i transfer the code from the connection.php to class.php it works fine.
Declare the $pdo as global in the above file connection.php.
Check Passing a variable from one php include file to another: global vs. not and Passing variables in PHP from one file to another
$stmt then it should be the case I believe.
So, the parent file has access to variables in both included files, but the included file doesn't have access to the other included file. Indeed it worked because of the global scope of it, however according to PHP semantics from linked questions it shouldn't be the right answer.
try {} catch()block, as shown in example 2 on this page: Connections and Connection management. That might tell you if the object is failing to be created properly.