referencing an existing object

Howdy,

    I am writing a program that has a handful of classes.  I would like to be able to get information from one object to the other.  I have a couple of my classes extending others, but are there other ways to do this?

For example: If I have a database class and a separate class that would like to execute an sql statement... class mydbclass {

    var $db;
    function mydbclass ($server,$username,$password,$database){
        $this->db=mysql_connect($server, $username, $password);
        mysql_select_db("$database",$db);
    }

    function dosql($sql){
        $result = mysql_query($SQL,$db);
    }

} class myotherclass {

    function myotherclass(){
        $sql="select * from mytable";

        #now, how can I use $mydbclass->dosql($sql) to
        #execute this statement?

        #I want to be able to build a bunch of html with
        #the resulting records and it wouldn't make
        #sence to build all that in my db class

    }

} Thanks! -- bernie www.bernieberg.com