ORM piece of mind 3

<?php

class ActiveTable
{
    public $name = 'noname';

    public function __construct($tableName)
    {
        $this->name = $tableName;
    }
}

class MemberTable extends ActiveTable
{

}

class ActiveRecord
{
    public function __construct()
    {
        echo "<pre>"; print_r($this); echo "</pre>";
    }

    public function insertIntoTable(ActiveTable $table)
    {
        $fields = array_map(
            function($element){
                if (is_string($element))
                    return "'$element'";
                if (is_int($element))
                    return $element;
                if (is_null($element))
                    return "NULL";
                if (is_float($element))
                    return "'$element'";
            },
            $this->getAsArray()
        );
        $r = 'INSERT INTO '.$table->name.' ('.implode(', ', array_keys($fields)).') VALUES ('.implode(', ', $fields).')';
        echo "<pre>"; print_r($r); echo "</pre>";
    }

    public static function createFromArray($fields = array())
    {
        $instance = new static();
        foreach ($fields as $fieldName => $fieldValue) {
            $instance->$fieldName = $fieldValue;
        }
        return $instance;
    }

    public function getAsArray()
    {
        $recordValues = array();
        foreach ($this as $fieldName => $fieldValue) {
            $recordValues[$fieldName] = $fieldValue;
        }
        return $recordValues;
    }
}

class Member extends ActiveRecord
{
    public $memberID = null;
    public $groupID = null;
    public $username = '';

    public function __construct()
    {
        parent::__construct();
    }
}

$table = new ActiveTable('prefix__members_lang_pl');

$ar = new ActiveRecord();
$ar->userID = 5;
$ar->insertIntoTable($table);

$ar = ActiveRecord::createFromArray(array(
    'username' => 'root',
    'password' => 'd033e22ae348aeb5660fc2140aec35850c4da997',
));
$ar->insertIntoTable($table);


$mem = new Member();
$mem->insertIntoTable($table);

$mem = new Member();
unset($mem->groupID);
$mem->insertIntoTable($table);