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COMPUTER SCIENCE PAPER TWO - Coggle Diagram
COMPUTER SCIENCE PAPER TWO
DATA REPRESENTATION
Number Bases
Binary (Base 2)
Binary Arithmetic
Binary Addition
When adding binary numbers together, there is a set of rules that must be followed.
Computers use Binary to represent information
This is because Binary only has two digits (1 & 0), and the ways computers store information is through switches that are either on (1) or off (0)
0000 0000 = 0
1111 1111 = 255
Hexadecimal (Base 16)
Why is Hexadecimal used in computing?
Easier to read
Easier to remember
Can be used to represent every possible colour shade
Note
: Information in Hexadecimal format does not take up less storage space
Information Units
One bit = 1 or 0
Nibble = 4 bits
Byte = 8 bits
Kilobyte = 1000 bytes
Megabyte = 1000 kilobytes
Gigabyte = 1000 megabyte
Terabyte = 1000 gigabytes
Character Encoding
ASCII
Unicode
Representing Images
Representing Sound
Data Compression
SQL & Relational Databases
Structured Query Language
Querying a database:
To search for a database's specific values
SELECT
field_name
FROM
table_name
WHERE
condition
ORDER BY
direction
SELECT = Designates which fields will be shown
SELECT * = Selects all fields in a table
FROM = Designates which tables will be queried
WHERE = Queries for information where only a specified condition is met
ORDER BY = Arranges select information in ascending or descending order
ORDER BY Asc
ORDER BY Desc
Inserting information into a database:
INSERT INTO
table_name
(
field_names
)
VALUES (
field_names
)
INSERT INTO = Designates which fields the data will be inserted into
VALUES = The values that will be inserted
Updating information in a database
UPDATE
table_name