1. Consider the following SQL query:

SELECT P.Pname, E.Fname, E.Lname

FROM EMPLOYEE E, PROJECT P, WORK_ON W

WHERE W.Hours < 40 AND E.Ssn = W.Essn AND W.Pno = P.Pnumber AND E.Sex = F;

(a) Draw the query graph.

(b) Draw the initial query tree.

(c) Draw the optimized query tree using heuristic optimization