Hotel Homework queries

HotelHomeworkQueries.txt

-- Arthur Khazbulatov (BBI1803)

-- Task 1
/*
π Number, rtName (
	σ s > 32 (
		Room ⨝ RoomType
	)
)
*/

-- Task 2
/*
π Number, rtName (
	σ ¬ isFinished (
		Stay ⨝ Room ⨝ RoomType
	)
)
*/

-- Task 3
/*
π Number, gName, email (
	σ Stay1.sid ≠ Stay2.sid
	∧ Stay1.gid = Stay2.gid (
		Guest ⨝ (
			ρ Stay1 (Stay)
			⨯ ρ Stay2 (Stay)
		) ⨝ Room
	)
)
*/

-- Task 4
/*
π country (
	σ tid = 4 (
		Guest ⨝ Stay ⨝ Room ⨝ RoomType
	)
) \
π country (
	σ tid ≠ 4 (
		Guest ⨝ Stay ⨝ Room ⨝ RoomType
	)
)
*/

-- Task 5
/*
π gid (
	σ totalNights < 3 (
		γ gid; sum(nights) -> totalNights (
			σ tid = 1 (
				Guest ⨝ Stay ⨝ Room ⨝ RoomType
			)
		)
	)
)
*/

-- Task 6
/*
π Number, nightPrice (
	σ ¬ isFinished ∧ ¬ seaView
	∧ (nightPrice < 10 ∨ nightPrice > 80) (
		Stay ⨝ Room ⨝ RoomType
	)
)
*/

-- Task 7

/*
π gName, email (
	Guest ⨝
	σ StayRoomType1.start < StayRoomType2.start
	∧ StayRoomType1.tid = 2
	∧ StayRoomType2.tid = 3 (
		ρ StayRoomType1 (Stay ⨝ Room ⨝ RoomType)
		⨯ ρ StayRoomType2 (Stay ⨝ Room ⨝ RoomType)
	)
)
*/

-- Task 8
/*
π gName, email (
	σ Stay1.start < Stay2.start
	∧ Stay1.nights ≤ Stay2.nights (
		Guest ⨝ (
			ρ Stay1 (Stay)
			⨯ ρ Stay2 (Stay)
		)
	)
)
*/

-- Task 9
π gName, email (
	Guest ⨝ Stay ⨝ Room ÷ RoomType
)