Concepts and Architecture Interview Question:

If a user executes a query which is already being used by a view exactly will oracle use already existing view to retrieve data or use the query executed by user?

Submitted by: Administrator

Oracle uses query executed by user because when you use a view name in an other query, it simply transform query.

select empid,name from emp; --- original
create view emp_view as select empid,name from emp; ----- view created as name emp_view

select * from emp_view where empid=100; ---------- this quey transform into
select * from (select empid,name from emp) where empid=100;

In above query it uses view because we use view name.

If we execute original query ,It does not have any view any to interpret,hence it uses original query.
Submitted by: Administrator