<?php
class DB
{
    protected $dialect = 'mysql';
    protected $host = 'localhost';
    protected $db;
    protected $user;
    protected $password;
    public $conn;

    function __construct($user, $pass, $db, $host='localhost', $dialect='mysql')
    {
        $this->db = $db;
        $this->user = $user;
        $this->password = $pass;
        $this->host = $host;
        $this->dialect = $dialect;
        $this->connect();
    }

    protected function connect()
    {
        try
        {
            $this->conn = new PDO(
                $this->get_db_string(),
                $this->user,
                $this->password
            );
        }
        catch(PDOException $e)
        {
            die("<h1>Error Establishing database connections</h1>");
        }
    }

    protected function get_db_string()
    {
        return sprintf(
            '%s:host=%s;dbname=%s',
            $this->dialect,
            $this->host,
            $this->db
        );
    }

    public function get_pk($table, $pk)
    {
        $rv = array();
        if($stm = $this->conn->prepare("SELECT * FROM {$table} WHERE id = :pk"))
        {
            $stm->execute(array('pk' => $pk));
            $rv = $stm->fetchAll(PDO::FETCH_ASSOC);
            $stm->closeCursor();
        }
        return count($rv) >= 1 ? $rv[0] : false;
    }
}