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## Thursday, 1 February 2018

### Normal Forms

GATE NOTES

Normal Forms in DBMS

Steps to find Normal Forms-

Partial Dependency - Partial dependency means that a non-prime attribute is functionally dependent on part of a candidate key.

Prime attribute - All candidate keys.

Non prime attribute - All non candidate keys.

Normal Forms in DBMS

Steps to find Normal Forms-

- Find Candidates key
- Find Prime attributes and Non prime attributes
- Check for Normal Forms, from starting from 1NF to higher order.

**Relational DBMS does not allow multi-valued or composite attribute.**

*1NF-***Relational DBMS does not allow partial dependency.**

*2NF-***Either LHS of an FD should be super key or RHS should be prime attribute.**

*3NF-*Partial Dependency - Partial dependency means that a non-prime attribute is functionally dependent on part of a candidate key.

Prime attribute - All candidate keys.

Non prime attribute - All non candidate keys.

## Tuesday, 30 January 2018

## Monday, 29 January 2018

### Static Single Assignment

GATE NOTES

Static Single Assignment

According to Static Single Assignment

Static Single Assignment

According to Static Single Assignment

- A variable cannot be used more than once in the LHS
- A variable should be initialised atmost once.

## Sunday, 28 January 2018

## Saturday, 27 January 2018

### Birthday Attack

**GATE NOTES**

**BIRTHDAY ATTACK**

- Birthday attack work only with random messages and not with chosen messages.

## Tuesday, 23 January 2018

GATE Notes,

Probability Formulas

Probability Range

0 ≤ P(A) ≤ 1

Rule of Complementary Events

P(A

^{c}) + P(A) = 1
Rule of Addition

P(A∪B) = P(A) + P(B) - P(A∩B)

Disjoint Events

Events A and B are disjoint iff

P(A∩B) = 0

Independent Events

Events A and B are independent iff

P(A∩B) = P(A) ⋅ P(B)

Conditional Probability

P(A | B) = P(A∩B) / P(B)

## Thursday, 11 January 2018

**GATE 2018 SYLLABI**

**Unique, Infinite, Many, Consistent, Inconsistent Solutions ?**

**1) a₁x + b₁y = c₁**

2) a₂x + b₂y = c₂

**If**

**a₁/a₂ ≠ b₁/b₂**

Than, its called unique solution.it means intercepting lines.Its also called consistent solution.

**If**

**a₁/a₂ = b₁/b₂ ≠ c₁/c₂**

Than its called no solution. It means parallel lines. Its also called inconsistent solution.

**If**

**a₁/a₂ = b₁/b₂ = c₁/c₂**

Than, its called infinite many soluiton. It means coincident lines.Its also called consistent solution.

For example-

## Wednesday, 10 January 2018

**Eigen Values and Characteristics roots ?**

To find Eigen values use, |

**A - λI**|

**= 0**

For characteristics roots,

**(**

**A - λI )X = 0**

When represents characteristics roots in matrix they called

**Eigen vectors.**

**If A is an n × n matrix, then the**

**sum of the n eigenvalues**of A is the

**trace**of A and the

**product of the n eigenvalues**is the

**determinant**of A.

Eigenvalues of a Matrix and its Transpose are same.

## Monday, 20 November 2017

### GATE 02

GATE 2016, SET I, 1 Mark

A processor can support a maximum of 4GB, where the memory is word-addressable (a word consists of two bytes). The size of address bus of the processor is at least _________bits.

Sol.

First we will convert 4GB in to Bytes

4GB = 230 X 4 = 230 X 22 = 232 Bytes

Given in problem, a word consist 2 Bytes,

So, no of words = 232 / 2 = 231

The size of address bus of the processor is at least 31 bits.