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Computer Science IGCSEPDF 124
142 pagesrevision 46930
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Date/Time
Character
Text/String/Alp
hanumeric
BOOLEAN
Integer/Numbe
r
REAL
Letters, numbers, or symbols.
Used for money, measurements, etc.
Single letter, number, or symbol
Letters, numbers, or symbols
Two possible values (e.g. Yes/No)
Dates and/or times in a standardized
format
● To differentiate between data items, there is a concept known as the
primary key; a field that uniquely identifies each record in a table.
● To ensure data integrity, validation rules that are used as checks.
● Each field can hold specific kinds of data, falling under the category of data
types.
DataType
Explanation
Example
67,526
YES ; NO
09/12/2005
42.6,-8.0
‘x’,’#’
“Hello world”