PHP Database lib

Database.php

<?php
	class Database{

		function __construct(){
			try{
				$this->pdo = new PDO('sqlite:storage.db'); // can be MySQL too
				$this->pdo->query("SET NAMES 'utf8'");
				$this->pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
				$this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
			}catch(PDOException $e){
				echo "<h1>Impossible de se connecter.</h1>";
				die();
			}
		}

		function exec($req, $val = []){ // Insert/Update/Delete
			$pdo = $this->pdo;
			$sql = $pdo->prepare($req);
			foreach($val as $key => $value){
				$sql->bindValue(":".$key, $value);
			}
			$sql->execute();
			return $pdo->lastInsertId();
		}
		function query($req, $val = []){ // query once
			$pdo = $this->pdo;
			$sql = $pdo->prepare($req);
			foreach($val as $key => $value){
				$sql->bindValue(":".$key, $value);
			}
			$sql->execute();
			$f = $sql->fetch();
			return $f;
		}

		function queryAll($req, $val = []){ // query all
			$pdo = $this->pdo;
			$sql = $pdo->prepare($req);
			foreach($val as $key => $value){
				$sql->bindValue(":".$key, $value);
			}
			$sql->execute();
			$f = $sql->fetchAll();
			return $f;
		}

		function rowCount($req, $val = []){ // get row count
			$pdo = $this->pdo;
			$sql = $pdo->prepare($req);
			foreach($val as $key => $value){
				$sql->bindValue(":".$key, $value);
			}
			$sql->execute();
			$c = $sql->rowCount();
			return $c;
		}
	}
?>