COMPUTER SCIENCE PART ONE: - created from Mind Map

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Representing Data

Databases

BINARY

DECIMAL

HEXADECIMAL

0 - 1

Binary = base 2 system - represents all data used in computer systems.

State of a component: 1 is ON, 0 is OFF

Converting from BIN:

DECIMAL: 0 = 2n, 1 = 2n + 1, where first value n = 0

Hexadecimal: Separate into nibbles, convert into HEX

101101010 = 1, 2, 5, 11, 22, 45, 90, 181, 362

11100010 = 1, 3, 7, 14, 28, 56, 113, 226

Tip: EACH NIBBLE IS WORTH UP TO THE 16th VALUE

101010011 = 1010 + 0011

11011110 = 1101 + 1110

A3

DE

Decimal = base 10 system used in real world. Each digit is a multiple of 10.

0 - 9

Converting from DEN:

BINARY: Divide by 2, and append remainder to binary. Flip value when done.

HEXADECIMAL: Divide by 16, and append remainder to hex. Flip value when done.

35 = 1 (17), 1 (8), 0 (4), 0 (2), 0 (1), 1 (0)

120 = 0 (60), 0 (30), 0 (15), 1 (7), 1 (3), 1 (1), 1 (0)

1 0 0 0 1 1

1 1 1 1 0 0 0

4562 = 285 (2), 17 (D), 1 (1), 0 (1)

143 = 8 (F), 0 (8)

11D2

8F

0 - F

Hexadecimal = base 16 system. Each digit is a multiple of 16. One hex digit for each nibble.

Easier to write HEX > BINARY

Converting from HEX:

BINARY: Separate each HEX digit and convert into nibbles:

DECIMAL: Work out decimal equivalent and times by multiples of 16...

2 + F = 0010 + 1111

E + A = 1110 + 1010

A + 2 = 16(10) + 1(2)

1+8 = 16(1) + 1(8)

162

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DATABASE TYPES:

USES AND APPLICATIONS OF DATABASES:

A single FLAT FILE table is useful for recording a limited amount of data.