Exercise 3.19 Briefly answer the following questions based on this schema:Emp(eid: intege...

Exercise 3.19 Briefly answer the following questions based on this schema:

Emp(eid:  integer, ename:  string, age:  integer, salary:  real)Works(eid:  integer, did:  integer, pct-time:  integer)Dept(did: integer, budget: real, managerid:  integer)

1. Suppose you have a view SeniorEmp defined as follows:
   

   CREATE VIEW SeniorEmp (sname, sage, salary)	AS SELECT E.ename, E.age, E.salary	   FROM Emp E	   WHERE E.age > 50

   
   Explain what the system will do to process the following query:
   

   SELECT S.snameFROM SeniorEmp SWHERE S.salary > 100,000

2. Give an example of a view on Emp that could be automatically updated by updating Emp.
3. Give an example of a view on Emp that would be impossible to update (automatically) and explain why your example presents the update problem that it does.