PDO Exception don't catch

Question

try{
line53 -> $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$ekle = $db->prepare("INSERT INTO data SET
name=?,
email=?");
$insert = $ekle->execute(array("$name","$e_mail"));
if($insert)
{
header ("Location:sucess.html");
}
else{
throw ("Error");
}
}
catch(PDOException $e){
echo $e->getMessage();
header ("Location:error.html");

}

this code don't catch exception. SQL isn't work.
Take error

Notice: Undefined variable: db in C:\xampp\htdocs\.....\.....php on line 53

Fatal error: Call to a member function prepare() on null in C:\xampp\htdocs\.....\....php on line 53

Answer 1

where is your pdo object established

Answer 2

<?php

$host = 'mysql:host=localhost;dbname=fro';
$user = 'root';
$pw = '';

try{
$db = new PDO($host,$user,$pw);
$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e){
echo 'Bağlantı hatası'.$e->getMessage();
}

$db->query("SET NAMES 'utf8'");

?>

I established different file.

Answer 3

where do you include your db connection in your query file