Brie?y 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 de?ned 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.sname FROM SeniorEmp S
WHERE S.salary > 100,000
2. Give an example of a view on Emp that could be automatically updated by up-dating Emp.
3. Give an example of a view on Emp that would be impossible to update (auto-matically) and explain why your example presents the update problem that it does.