Nesting queries within active record

[eluser]m4rw3r[/eluser]
I've done some peeking into ActiveRecord's code, and that is what it does, from my understanding of Ruby.

It does a join, and then does something like (this is in PHP, and overly simplified):

Code:

foreach($rows as $row)
{
    if( ! isset($result[$row['id']]))
    {
        $result[$row['id']] = new Manufacturer($row);
    }

    $result[$row['id']]->cars[] = new Car($row); // constructor will filter the data
}