Creating View with a condition

[hatebin]

Hello.

I've got an exaple data base for hr account from Oracle.
My goal is to create a view which contains empno,ename and deptno from EMP, but than i can only add rows with condition deptno=20.

I've cameup with

create or replace view d20emp as
select 
empno as num, 
ename as name, 
deptno as department 
from emp where deptno=20;

Any ideas how to add this cinde of condition ?

[debasisdas]

Your code is perfectly fine.