Handling DB query errors

I am not sure about how to properly handle DB Query errors. Here is a typical query where the possible is NOT handled. Any suggestions are welcomed e.g. how to code the query; how to have an error page; how to handle errors produced by the Interbase server. /* Get member data */ function db_get_member_data($dbh, $member_id) {

    $stmnt = "SELECT * FROM Member WHERE MEM_MEM_ID='" . $member_id . "'";
    $sthdl = ibase_query($stmnt,$dbh);
    return $sthdl;

} Todd --