Database-Management-System

Question 256

An expression in the domain relational calculus is of the form:

A	{P(x1,x2,…,xn) \| ⟨x1,x2,…,xn⟩}
B	{x1,x2,…,xn \| ⟨x1,x2,…,xn)}
C	{x1,x2,…,xn \| x1,x2,…,xn}
D	⟨x1,x2,…,xn⟩ \| P(x1,x2,…,xn)}

Database-Management-SystemRelational-CalculusNIC-NIELIT Scientist-B 2020Video-Explanation

Question 256 Explanation:

Domain relational calculus (DRC) is a calculus that was introduced by Michel Lacroix and Alain Pirotte as a declarative database query language for the relational data model.
In DRC, queries have the form:
{(X1,X2,….,Xn) | p( X1,X2,….,Xn ) where each Xi is either a domain variable or constant, and p(X1,X2,….,Xn)} denotes a DRC formula. The result of the query is the set of tuples X1 to Xn that make the DRC formula true.
This language uses the same operators as tuple calculus, the logical connectives ∧ (and), ∨ (or) and ¬ (not). The existential quantifier (∃) and the universal quantifier (∀) can be used to bind the variables.

Correct Answer: D

Question 256 Explanation:

Domain relational calculus (DRC) is a calculus that was introduced by Michel Lacroix and Alain Pirotte as a declarative database query language for the relational data model.
In DRC, queries have the form:
{(X1,X2,….,Xn) | p( X1,X2,….,Xn ) where each Xi is either a domain variable or constant, and p(X1,X2,….,Xn)} denotes a DRC formula. The result of the query is the set of tuples X1 to Xn that make the DRC formula true.
This language uses the same operators as tuple calculus, the logical connectives ∧ (and), ∨ (or) and ¬ (not). The existential quantifier (∃) and the universal quantifier (∀) can be used to bind the variables.

A	{P(x1,x2,…,xn) \| ⟨x1,x2,…,xn⟩}
B	{x1,x2,…,xn \| ⟨x1,x2,…,xn)}
C	{x1,x2,…,xn \| x1,x2,…,xn}
D	⟨x1,x2,…,xn⟩ \| P(x1,x2,…,xn)}

Normalization

Database-Management-System

Normalization

Database-Management-System

Database-Management-System

Mandeep Singh