Hi

way does your freind whants to use a varchar as a primary key? i suggest you use a number column as a primary key for the id column and use the varchar2 column as a use id column (the id the user actual see on the form). use unique index on this field + not null, and you have no probelms. better work this way. and as an argument to support your case you can tell that in oracle applications erp suite this is normaly what is done. the varchar is the id for the user and the number system generated id is for the select statment inside the system.