Match the followings:

Column 1	Column 2
(a) Alternate Key	(A) Number of tuples in a relation
(b) Relation	(B) Used to specify rules for the data in a table
(c) Cardinality	(C) A table in a relational database
(d) Constraint	(D) A candidate key that is not a Primary Key

Five friends plan to start a new business. However, they have a limited budget and limited computer infrastructure. Which benefits of cloud services they can avail to launch their startup?

Write the output for the following print statements in Python.

Sub_Teacher = {"English":"Mr. Gill", "Maths": "Mr. R.N. Pandey", "IP":"Ms. Renu Ahuja", "Physics": "Ms. Meenu Lal", "Chemistry":"Ms. Mamta Goel"}
print(Sub_Teacher['Chemistry'])  #Line1
print(Sub_Teacher.keys())       #Line2
print(len(Sub_Teacher))        #Line3

Rohit, a Librarian has created a Table Book with the following fields:

Bookid, Bookname, Author and Price. He has entered 20 records in the table.

Which command should he use to do the following:

(i) To change the price of Computer Science book from 450 to 500.

(ii) To insert Primary Key in the table.

(iii) What is the difference between delete and drop command.