count(*) from view??

create table test (id int, user_name char(30));
insert into test values (1, 'John');
insert into test values (2, 'George');

create view v_test as select * from test where user_name = 'John';

select count(*) from v_test;
 count
-------
     2
(1 row)      Why?...Should returns 1

select count(*) from test where user_name = 'John';
 count
-------
     1
(1 row)

--Greg--