Another small new feature in Oracle 11g PL/SQL: you can directly use sequence.nextval (and sequence.currval). It is not necessary anymore to do something like select sequence.nextval into l_seq from dual in your PL/SQL block. A small example: 

declare  l_seq number;begin  l_seq := oe.orders_seq.nextval;  dbms_output.put_line('Value of orders_seq.nextval = '||to_char(l_seq));end;

SQL>

Value of orders_seq.nextval = 1000

PL/SQL-procedure is geslaagd.