Consider the following view, dept_summary, defined on the company database in figure 5.6: create view dept_summary (d, c, total_s, average_s) as select dno, count (*), sum (salary), avg (salary) from employee group by dno; state which of the following queries and updates would be allowed on the view. if a query or update would be allowed, show what the corresponding query or update on the base relations would look like, and give its result when applied to the database in figure 5.6.
a. select * from dept_summary;
b. select d, c from dept_summary where total_s > 1; 238 chapter 7 more sql: complex queries, triggers, views, and schema modification.
c. select d, average_s from dept_summary where c > ( select c from dept_summary where d = 4);
d. update dept_summary set d = 3 where d = 4; e. delete from dept_summary where c > 4;