PHP - Database connection using PDO

gistfile1.txt

<?php
 
// you can choose from MySQL and SQLite
define('DB_DRIVER', 'mysql');
// SQLite don't use host parameter
define('DB_HOST', 'localhost');
define('DB_USER', 'login');
define('DB_PASS', 'password');
// In case of SQLite usage, change it to path/to/your.db, for example
define('DB_NAME', 'testdb');
 
function initDB(){
    // Switch correct pattern for chosen DBMS. 
    // You can add your own patterns for PostgreSQL or MS SQL, for example 
    if(DB_DRIVER=='mysql')
        $pattern = '%1$s:host=%2$s;dbname=%3$s';
    elseif(DB_DRIVER=='sqlite')
        $pattern = '%1$s:%3$s';
    else
        die("Can't create DB instance! Reason: Unsuported DB driver");
     
    // Construct correct data source name for chosen database type
    $dsn = sprintf($pattern, DB_DRIVER, DB_HOST, DB_NAME);
 
    try{
        $pdoInst = new PDO($dsn, DB_USER, DB_PASS);
        $pdoInst->setAttribute(PDO::ATTR_ERRMODE, 
                                PDO::ERRMODE_EXCEPTION);
    }catch(PDOException $e){
        // Stop script and throw message if error occurred
        die($e->getMessage());
    }
     
    // Let us know that all is ok. Only for debug.
    echo 'PDO Instance created!';
    return $pdoInst;
}
 
?>