ORA-01732: what functions are allowed for view creation?

Question

Hi,
i try to create a view, where i can delete rows. Here my view
CREATE OR REPLACE VIEW myview as select * from (select * from orders order by starttime) where rownum < 4
If i try to delete a row i get:
SQL Error: ORA-01732: Datenmanipulationsoperation auf dieser View nicht zulässig
(translation: data manipulation for this view not allowed)
Breaks the rownum the view? I tested it with rank() over and this breaks it too...

Answer 1

sql>
CREATE OR REPLACE VIEW myview
as
select * from (select * from emp order by hiredate) where rownum<4;
View created
sql>
create or replace trigger trig1
instead of delete
on myview
for each row
begin
delete from emp
where empno = :old.empno;
end;
Trigger created.
sql>select * from myview;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
7499  ALLEN  SALESMAN  7698  20-FEB-81  1600  300  30 
7521  WARD  SALESMAN  7698  22-FEB-81  1250  500  30 
7566  JONES  MANAGER  7839  02-APR-81  2975     20 
sql>
delete from myview
where rownum=1;
1 row deleted.
sql>select * from myview;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO 
7521  WARD  SALESMAN  7698  22-FEB-81  1250  500  30 
7566  JONES  MANAGER  7839  02-APR-81  2975     20 
7698  BLAKE  MANAGER  7839  01-MAY-81  2850     30
Message was edited by:
        jeneesh