unset()ing classes...

I have a class that I use for all things ODBC. To use the class I do things
similar to this:

$cls_odbc = new odbc_ops;
$cls_odbc->db_open();
$query = odbc_exec($cls_odbc->db_conn(), "SELECT * FROM " . $str_page_name .
" ORDER BY display_order") or die (odbc_errormsg());
$arr_sections = array();
while($row = odbc_fetch_array($query))
$arr_sections += array($row['f_key'] => $row['section_name']);
$cls_odbc->db_close();
unset($cls_odbc);


My question is... Is the last line - unset($cls_odbc); - really needed?
Does the class instance get properly destroyed when the function goes out of
scope?


Plankmeister.