Reference no: EM13509179

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.