4) Based on the following database schemas: Homestay (homestayNo (PK), homestayName, address, telNo, city) Room (roomNo, homestayNo (PK), type, price) Booking (homestayNo, guestNo (PK), dateFrom, dateTo, roomNo) Guest (guestNo (PK), guestName, guestAddress, guestTelNo)

Assume the following indexes exist: a) a hash index with no overflow on the roomNo and homestayNo as a composite primary key in Room; b) a clustering index on the foreign key attributes homestayNo in Room; c) a B+-tree index on the price attribute in Room; d) a secondary index on the attribute type in Room.

nTuples(Room) = 20000 bFactor(Room) = 200 nTuples(Homestay) = 100 bFactor(Homestay) = 40 nTuples(Booking) = 100000 bFactor(Booking) = 60 nDistincthomestayNo(Room) = 50 nDistinctroomNo(Booking) = 150 nDistincttype(Room) = 10 nDistincthomestayName(Homestay) = 50 nDistinctprice(Room) = 500 maxprice(Room) = 500 minprice(Room) = 200 nLevelstype(I) = 2 nLevelshomestayNo(I) = 2 nLfBlocksprice(I) = 50 nLevelsprice(I) = 2 Log2100 = 6.64 Log250 = 5.64

Calculate the SELECTION CARDINALITY and ESTIMATED COST for:

Selection: type=Flat price < 200 (Room)