The world’s Largest Sharp Brain Virtual Experts Marketplace Just a click Away
Levels Tought:
Elementary,Middle School,High School,College,University,PHD
| Teaching Since: | May 2017 |
| Last Sign in: | 398 Weeks Ago, 2 Days Ago |
| Questions Answered: | 66690 |
| Tutorials Posted: | 66688 |
MCS,PHD
Argosy University/ Phoniex University/
Nov-2005 - Oct-2011
Professor
Phoniex University
Oct-2001 - Nov-2016
Again using the Hotel schema, draw a relational algebra tree for each of the following queries and use the heuristic rules given in Section 21.3.2 to transform the queries into a more efficient form. Discuss each step and state any transformation rules used in the process.
(a) SELECT r.roomNo, r.type, r.price
FROM Room r, Booking b, Hotel h
WHERE r.roomNo = b.roomNo AND b.hotelNo = h.hotelNo AND
h.hotelName = ‘Grosvenor Hotel’ AND r.price > 100;
(b) SELECT g.guestNo, g.guestName
FROM Room r, Hotel h, Booking b, Guest g
WHERE h.hotelNo = b.hotelNo AND g.guestNo = b.guestNo AND h.hotelNo = r.hotelNo AND
h.hotelName = ‘Grosvenor Hotel’ AND dateFrom >= ‘1-Jan-04’ AND dateTo
Hel-----------lo -----------Sir-----------/Ma-----------dam----------- Â----------- -----------Tha-----------nk -----------You----------- fo-----------r u-----------sin-----------g o-----------ur -----------web-----------sit-----------e a-----------nd -----------acq-----------uis-----------iti-----------on -----------of -----------my -----------sol-----------uti-----------on.-----------Ple-----------ase----------- pi-----------ng -----------me -----------on -----------cha-----------t I----------- am----------- on-----------lin-----------e o-----------r i-----------nbo-----------x m-----------e a----------- me-----------ssa-----------ge -----------I w-----------ill----------- be----------- ca-----------tch-----------