1(a). Find out the Cartesian product (A X B) of the given pairof sets. Marks: 5
ID: 3615241 • Letter: 1
Question
1(a). Find out the Cartesian product (A X B) of the given pairof sets. Marks: 5
A => Set of first letterof the names ofcountries = A = { P, U, I }
B => Set of numbers denotingUniversity numbers = B = {010, 011}
1(b). Consider the table below:
Room Table
RoomNo
hotelNo
Type
price
10
001
A
100
15
002
B
50
20
002
C
50
25
003
A
150
Show the relation that will be produced by the followingrelational algebra operation:
hotelNo ( price > 50(Room)) Marks:10
RoomNo
hotelNo
Type
price
10
001
A
100
15
002
B
50
20
002
C
50
25
003
A
150
Explanation / Answer
1(a). The Cartesian product (A X B) means the product of bothsets A and B in such a way that every element of A is made a pairof every other element of B. It is written by AxB, also note thathere A is written first so first element of every pair will belongto A and second to B. The product is shown below
AxB= { (P, 010), (P, 011), (U, 010), (U, 011), (I, 010), (I,011) }
1(b). hotelNo ( price > 50(Room))
Here, first the operation in the brackets ( i.e.price > 50 (Room) ) will be performed. This isSelection operation and according to the given condition, it willgive us all the rows in which the price is greater than 50, i.e.the second and the last row of the table.
RoomNo
hotelNo
Type
price
10
001
A
100
25
003
A
150
Now, the outer operation (i.e. hotelNo called Projection) is performed on the table obtained above. Hereaccording to the given condition, the column named "hotelNo" haveto be shown. So, after performing this operation we get
hotelNo
001
003
So, the answer of the operations hotelNo (price > 50 (Room)) is
hotelNo
001
003
RoomNo
hotelNo
Type
price
10
001
A
100
25
003
A
150
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.