Simple ESQL-C Problem on INFORMIX-SE

Hallo, I want to use statements with variable number of parameters. Example : $update arti set ar401=ar401 + $menge, ar406=ar406 - $menge, ar509=ar509 + $menge, . . ar510=ar510 + $wert, ar503=ar503 + $menge, ar504=ar504 + $wert where ar001=$lgteilnr and ar002=$teilnr; The problem is that the number of colums to update is variable. I could use the prepair/declare/execute mechnism to generate a variable statement, but the number of input-variables is variable too. I think the descriptor methode is not usefull in this case, because the are only two or three kinds of values for the variables. In PL-SQL ORACLE it is possible to define local hostvariables, within an begin-end block, that can used in the select/update statement. With INFORMIX it is only possible in SPL Statements !??? Or how can I solve my problem with INFORMIX ? best regards Dirk Niemeier