Organisation And Structure Of Data Flashcards
Define denary
Base 10 (0,1,2,3,4,5,6,7,8,9)
Define binary
Base 2 (0,1)
Define hexadecimal
Base 16 (0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F) used as shorthand for binary
How to double binary
Shift all 1 to the left
How to divide binary
Shift all 1 to the right
Binary addition
0+0=0
0+1=1
1+1=10
1+1+1=11
Define pixel
A small coloured dot on a computer display
Define bitmap
A stored array of pixels that create an image
Define vector
Images stored as instructions to draw a geometric shape
Define sample rate
The number of audio samples captured each second. The higher the sample rate, the better the quality but larger the file
Define bit depth
The number of bits available for each clip e.g. bit depth 4 (0101) or bit depth 8 (01010110)
Define bit rate
The number of bits used per second of audio
Define metadata
Set of data that describes other data
Define colour bitmap image
Like a black and white bitmap but with longer binary numbers that represents how much red, green and blue is required in the colour of a pixel
Colour depth to number of colours
1 bit - 2
2 bit - 4
3 bits - 8
8 bits - 256
16 bits - 65,536
24 bits - 16.7 million
32 bits - 4.3 billion
Examples of metadata on music files
Genre of music
Date created
Location
Size
Dimensions
Define integer
Whole numbers, positive or negative
Define real
Numbers including fractions or decimal points
Define Boolean
True or False, 1 or 0
Define character
Letter, digit, punctuation, or any other symbol
Define string
A sequence of characters
Define character set
A table that maps a character to a corresponding binary digit e.g ASCII
Define data sructure
A specific way of organising data so it can be processed efficiently
Define record
A structure containing related data of different data types
Define primary key/key field
A unique identifier for each record e.g ID number
Define array
A structure containing a fixed number of data items, which must be the same data type e.g list
Code for traversing an array (using each item in the list)
myArray[array length]
for i = 0 to end of array
print myArray[i]
next i
Code for insertion in an array
myArray[array number] = new entry
Code for deletion in an array
myArray[array number] = “”
How to store two dimensional arrays
myArray[row,column]
Code for traversing a two dimensional array
myArray[row,column]
for i = 0 to end of row
for j = 0 to end of column
print myArray [i, j]
next j
next i
Define validation
Ensures that data entered is reasonable
Types of validation check (5)
Presence
Format
Length
Data Type
Range
Definition and code for presence check
Checks if the field has been left blank
if data entered = “” then
output error message
end if
Definition and code for format check
Checks for a specific pattern
if data entered <> format(…) then
output error message
end if
Definition and code for length check
Checks for certain or sensible length
if len(data entered) <> number then
output error message
end if
Define data type check
Checks input data is a particular data type
Definition and code for range check
Checks data is within a specified range
if data entered < minimum
OR data entered > maximum then
output error message
end if
Define verification check
Ensures that data entered is consistent
Types of verification check
Double-entry
Screen based/ visual check
Check digit
Definition and code for double-entry
Checks for comparing two versions of a data input
if password <> reTypePassword then
output error message
end if
Define screen based/ visual check
Makes the user check that the information is correct
Define check digit
Uses calculations to check. Repeats the calculation and checks if the output is the same to verify
