$dados = Connection::select("SELECT * FROM tabela");

$rows = $dados->fetchAll();
$count = count($rows);

<?php

class Connection {

    public static $conn;

    public static function open($name) {
        if (file_exists("config/{$name}.ini")) {
            $db = parse_ini_file("config/{$name}.ini");
        } else {
            throw new exception("Arquivo '$name' nao encontrado");
        }

        $user = isset($db['user']) ? $db['user'] : NULL;
        $pass = isset($db['pass']) ? $db['pass'] : NULL;
        $name = isset($db['name']) ? $db['name'] : NULL;
        $host = isset($db['host']) ? $db['host'] : NULL;
        $type = isset($db['type']) ? $db['type'] : NULL;
        $port = isset($db['port']) ? $db['port'] : NULL;


        switch ($type) {
            case 'pgsql':
                $port = $port ? $port : '5432';
                $conn = new PDO("pgsql:dbname={$name}; user={$user}; password={$pass};host=$host;port={$port};");
                break;
            case 'mysql':
                $port = $port ? $port : '3306';
                $conn = new PDO("mysql:host={$host};port={$port};dbname={$name}", $user, $pass);
                break;
            case 'sqlite':
                $conn = new PDO("sqlite:{$name}");
                break;
            case 'ibase':
                $conn = new PDO("firebird:dbname={$name}", $user, $pass);
                break;
            case 'oci8':
                $conn = new PDO("oci:dbname={$name}", $user, $pass);
                break;
            case 'mssql':
                $conn = new PDO("mssql:host={$host},1433;dbname={$name}", $user, $pass);
                break;
        }

        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        self::$conn = $conn;
    }

    public static function select($sql) {
        return self::$conn->query($sql);
    }

    public static function exec($sql, $ret_id = false) {
        $retorno = self::$conn->exec($sql);
        if ($ret_id)
            $retorno = self::$conn->lastInsertId();
        return $retorno;
    }

    public static function close() {
        self::$conn = null;
    }

}

host = localhost
name = sistema
user = root
pass = root
type = mysql