SOS，求救

在oracle里面增加字段内容如下：
if(action.equals("add")){
staffid=request.getParameter("staffid");
sqlstr="select count(*) from user1 where username='"+staffid+"'";
rs=stmt.executeQuery(sqlstr);
while(rs.next()){
dupcount=rs.getInt(1);
}
if(dupcount>=1){
//out.println("对不起，数据库中已有此纪录！");
response.sendRedirect("error.jsp?mess=00001");
return;
}
sqlstr="select s_staff.nextval from dual ";
rs=stmt.executeQuery(sqlstr);
int idnext=0;
while(rs.next()){
idnext=rs.getInt(1);
}
sqlstr="insert into user1 (id,username) values("+idnext+",'"+staffid+"')";
System.out.println("sqlstr-add=["+sqlstr+"]");
stmt.executeUpdate(sqlstr);

我现在采用的是sql server2000，可是sqlstr="select s_staff.nextval from dual ";语句是在oracle里面才采用的，所以不知道在sql server2000这段代码该如何写，那位帮我一下，谢谢啦