OOP PHP please help me understand

1

I started learning OOP PHP from yesterday. Learnt the basic concept. Now what i am trying to do is create a class that shows data from a table. provided the table name and other parameters. here is the code.


<?php

$conn=mysql_connect('localhost','root','') or die("Could not connect to server.");
$db=mysql_select_db("recess",$conn) or die("Database recess not found.");

class Database
{
	public function selects($table, $rows = '*', $where = null, $order = null)
	{
		$q = 'SELECT '.$rows.' FROM '.$table;
        if($where != null)
            $q .= ' WHERE '.$where;
        if($order != null)
            $q .= ' ORDER BY '.$order;

        $query = @mysql_query($q);
		if($query)
        {
// I do not understand this part untill "<END>" comment is seen
            $this->numResults = mysql_num_rows($query);
            for($i = 0; $i < $this->numResults; $i++)
            {
                $r = mysql_fetch_array($query);
                $key = array_keys($r);
                for($x = 0; $x < count($key); $x++)
                {
                    // Sanitizes keys so only alphavalues are allowed
                    if(!is_int($key[$x]))
                    {
                        if(mysql_num_rows($query) > 1)
                            $this->result[$i][$key[$x]] = $r[$key[$x]];
                        else if(mysql_num_rows($query) < 1)
                            $this->result = null;
                        else
                            $this->result[$key[$x]] = $r[$key[$x]];
                    }
// <END> Untill here
                }
            }
            return true;
        }
        else
        {
            return false;
        }
	}
	public function getResult()
    {
        return $this->result;
    }
} 

?>

<?php

	$show = new Database();
	$show->selects("category");
	echo $show->getResult();   //this simply prints  "Array"  I dunno why

?>

Please help me understand.

Thanks in advance