what is pdo connection in php code example

Example 1: php pdo connection

$host     = "localhost";//Ip of database, in this case my host machine    
$user     = "root";	//Username to use
$pass     = "qwerty";//Password for that user
$dbname   = "DB";//Name of the database

try {
    $connection = new PDO("mysql:host=$host;dbname=$dbname", $user, $pass);
    $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

}catch(PDOException $e)
{
  echo $e->getMessage();                         
}

Example 2: how to connect pdo php database

<?php
$servername = "localhost";
$username = "username";
$password = "password";

try {
  $conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
  // set the PDO error mode to exception
  $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
  echo "Connected successfully";
} catch(PDOException $e) {
  echo "Connection failed: " . $e->getMessage();
}
?>