DML on a view

Question

Hi
I created a view as below
create or replace view emp_dept(ename,empno,deptno,dname) as
select e.ename,e.empno,e.deptno,d.dname
from emp e,
dept d
where e.deptno=d.deptno;
then i wanted to insert one record
insert into emp_dept(ename,empno) values('abc',89);
It is giving me a error
ora-01779:cannot modify a column which maps to a nonkeypreserved table.
when both the fields are from emp table which is a key preserved table in this joined view why is it giving me a error? any idea???
regards,
satya

Answer 1

It's not about the emp table being key preserved, but the dept table:
SQL> create or replace view emp_dept(ename,empno,deptno,dname) as
  2  select e.ename,e.empno,e.deptno,d.dname
  3  from emp e,
  4  dept d
  5  where e.deptno=d.deptno
  6  /
View is aangemaakt.
SQL> select constraint_name, constraint_type, table_name, r_constraint_name
  2    from user_constraints
  3   where table_name in ('EMP','DEPT')
  4     and constraint_type in ('P','R')
  5  /
CONSTRAINT_NAME                C TABLE_NAME                     R_CONSTRAINT_NAME
EMP_PK                         P EMP
1 rij is geselecteerd.
SQL> insert into emp_dept(ename,empno) values('abc',89)
  2  /
insert into emp_dept(ename,empno) values('abc',89)
FOUT in regel 1:
.ORA-01779: cannot modify a column which maps to a non key-preserved table
SQL> alter table dept add constraint dept_pk primary key (deptno)
  2  /
Tabel is gewijzigd.
SQL> insert into emp_dept(ename,empno) values('abc',89)
  2  /
1 rij is aangemaakt.Regards,
Rob.
Message was edited by:
Rob van Wijk
Sorry padders, the reply should have been addressed to user451372.