Logical or Boolean

• Data stored in Boolean form can only be one of two available values.

• Think of a light switch – it’s on or off.

• Examples include:

YES TRUE 1

FALSENO 0

M

F

Alphanumeric

• Alphanumeric data is any combination of letters, numbers and symbols (@#¬|\/>< etc.)

• This data type is also known as a string or text.

• Examples:

£4987 is a lot to pay for a badger

I like fish

DL61 ABC

@*!#

Alphanumeric Continued…

• Alphanumeric or text/string is used to hold telephone numbers.

• In a computer, telephone numbers are stored as text.

• This is because the telephone number contains a leading zero and spaces.

Real

• A real number is one which has decimal places.

• Examples:

3.1417512.418.01

Integer

• Integer numbers are whole numbers, no bits, no decimal places.

• Examples:

5

999999

-54

Date• Dates can be stored in many different forms.

• In the UK we write the date in the form DD/MM/YYYY e.g. 31/12/2014.

• In the US, they use the form MM/DD/YYYY e.g. 12/31/2014.

• Examples:15/08/1999 2009/11/30 12/31/1999

Other Data Types

• Currency – Software will automatically add £ or $ to data and include decimal places. E.g. £22.99.

• Image – Some databases will allow an image to be stored, for example a photo of a criminal and their fingerprints on a crime database.