3i Infotech Placement: Sample Questions 876 - 878 of 1245

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Question 876

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Describe in Detail

Essay▾

What is Relational Calculus?

Explanation

  • Relational calculus is an query language which is non procedural, and instead of algebra it uses mathematical predicate calculus.
  • The relational calculus is not the same like that of differential and integral calculus in mathematics, but takes its name from a branch of symbolic logic termed as predicate calculus.
  • When applied to databases, it is found in two forms. These are
    • Tuple relational calculus which was originally proposed by Codd in the year 1972 and
    • Domain relational calculus which was proposed by Lacroix and Pirotte in the year 1977

Question 877

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Describe in Detail

Essay▾

What is a concrete class?

Explanation

  • A concrete class defines useful object that can be instantiated as an automatic variable on the program stack.
  • The implementation of a concrete class is defined.
  • It is not intended to be a base class.
  • Concrete is the default type of class such class can have direct instances.
  • A derived class that implements all the missing functionality is the concrete class in inheritance.
Given the Concrete Classes of Shape Class

Question 878

Question

MCQ▾

If a sum of money compound annually amounts of thrice itself in 3 years. In how many years will it become 9 times itself?

Choices

Choice (4)

a.

6

b.

10

c.

12

d.

8

Answer

a.

Explanation

A sum of money compound annually amounts of thrice itself in 3 years.

We know that,

Where, A = Amount, P = Principal, R = rate and n = number of years

As per the information,

So,

We are asked to find the number of years in which amount will be 9 times the principal.

Let in n years amount will be 9 times the principal.

So,

From equation (i) ,

So,

So, in 6 years amount will be 9 times the principal sum.

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