I GUESS THAT U UPDATE THE DATABASE ON A CLICK EVENT OF A SUBMIT BUTTON;ASSUME THE CAPTION OF THE BUTTON IS "UPDATE" AND THE BUTTON NAME "btnUPDATE".TRY THE FOLLOWING METHOD.IT COULD WORK
<%
String BUTTON=request.getParameter("btnUPDATE");
if(BUTTON==null)BUTTON="NULL" ;
if (BUTTON.equals("UPDATE")){
://WRITE THE REQUIRED DATABASE UPDATE CODE HERE
://WITHIN THE IF CONDITION
}
%>