Uncaught exception 'PDOException' message 'invalid data source name'

Question

I´m trying to connect to my database with PDO and show some blogposts on a page. However I´m getting this error message:

Fatal error: Uncaught exception 'PDOException' with message 'invalid data source name' in index.php on line 61...

I´ve been searching for help but really can´t figure out what is wrong so if anyone have any idea it is much appreciated!

I have a separate connect.inc.php file which is included in the index.php file.

This is the connect.inc.php file:

<?php
class DB extends PDO
{
function database_connection() {
   $db_host = "localhost";
   $db_name = "blogdata";
   $db_user = "username";
   $db_pass = "password";
   try {
   global $db_host, $db_name, $db_user, $db_pass;
   $pdo = new PDO("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);
   }
   catch(PDOException $e) {
   die( 'Query failed: ' . $e->getMessage() );
}
}
}
?>

And this is the section in the index.php file which is pointed out in the error message:

<?php
    require 'connect.inc.php';  
    $db = new DB('blogdata');

    $query = "SELECT * FROM blogposts";
    if ($result = $db->query($query)) {
    while ($row = $result->fetch(PDO::FETCH_ASSOC)) {
        echo ' 
            <section id="content">
            <article class="post_title"><h3> ', $row['title'],' </h3></article>
            <article class="post_message"> ', nl2br ($row['message']),' </article>
            <article class="post_time"> ',$row['time'],' </article>
            </section>
            ';
        }
    } ;
    ?>

Answer 1

Gotcha.

For some reason you are extending your class from PDO. So, your 'blogdata' is taken as a DSN.

Just get rid of your DB class and use raw PDO

connect.inc.php:

<?php 
$db_host = "localhost";
$db_name = "blogdata";
$db_user = "username";
$db_pass = "password";
$db = new PDO("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

index.php:

<?php
require 'connect.inc.php'; 

$query = "SELECT * FROM blogposts";
$result = $db->query($query);
while ($row = $result->fetch(PDO::FETCH_ASSOC)) {