php pdo Call to a member function query() on null [duplicate] - php

Question

This question already has answers here:
Giving my function access to outside variable
(6 answers)
Closed 6 years ago.
// db.php
$db = array();
$db['host'] = '127.0.0.1';
$db['login'] = 'root';
$db['pass'] = '';
$db['name'] = 'edziennik';
$db_conn = new PDO('mysql:host='.$db['host'].';dbname='.$db['name'].';charset=utf8mb4', $db['login'], $db['pass']);
login_system.php
<?php
require_once('cfg/db.php');
function validate_data($l, $p)
{
$query = "SELECT * FROM e_users WHERE login='"+$l+"' AND password='"+$p+"'";
$stmt = $db_conn->query($query);
$row_count = $stmt->rowCount();
if($row_count===1)
return true;
else
return false;
return false;
}
Error: Call to a member function query() on null
Adding global prefix don't helped.
I lost lot of time to fix it, so i ask you.

Answer 1

$db_conn doesn't exist in the validate_data scope. Pass it in as an argument.
<?php
require_once('cfg/db.php');
function validate_data($db_conn, $l, $p)
{
$query = "SELECT * FROM e_users WHERE login='".$l."' AND password='".$p."'";
$stmt = $db_conn->query($query);
$row_count = $stmt->rowCount();
if($row_count===1)
return true;
else
return false;
return false;
}
And when you call it, pass in the connection.
$check = validate_data($db_conn, $whateverLIs, $whateverPIs);
Edit: -Fixed concat operator as noted by #Bamar.