Data types

1AQA ICT AS Level © Nelson Thornes 2008
Types of data

• Reminder: What is data
• Data represents raw facts and figures or a set
of values.
• Types of data: can be in othe formats as well
as text and numbers. It could also be in the
format of moving images or sound.
• When storing information in a database such
as Access, Oracle or MYSQL it is important
you get the data type right as it will store the
information based on the data type.

Data types
Is data always words or numbers?
No. Here are the data types available in Access.
Click on one or more
hyperlinks to find out
more.
Text, Memo, Number,
Date/Time, Currency,
AutoNumber, Yes/No,
OLE Object, Hyperlink,
Lookup Wizard
Click here when you have finished investigating
data types.

In a database, what field names would expect data
type text?
Surname
Address line 1
Mode of transport
Telephone number*
*Click here for more information on telephone
numbers or here to continue.
Text

Why is 01225 843878 treated as text?
Although the data is made up of numbers this is
really a code. Telephone numbers used to contain
letters as well.
Databases can include calculated fields but
calculations cannot be formed with telephone
numbers.
Click here to continue with the presentation.
Telephone number

Memo fields enable you to enter continuous, free
response text. You do not have to specify the field
length as you would with a text field.
The maximum length is 65,535 characters.
Click here to continue.
Memo

Number
This one is very straightforward. It is used to store
numerical data.
Remember that Access can use these fields to
carry out calculations – a calculated field.

You can set these fields to store a date or time or
both. The Input Mask lets you choose how you want
it displayed.
Date and Time

Currency fields are the same as numbers but set to 2
decimal places.
They also display the currency symbol, for example
£, €.
Currency

This field will automatically number your records.
It will not allow duplicates so you could use this field
as the key field.
Auto number

A logical field expects the data to be Yes or No, or
True or False. Data entry is done by ticking the box
using the mouse. James and Maureen have
passed, David has not.
Yes/No

This data type enables you to include pictures or
sounds in your database.
OLE Object

This will put a hyperlink on your reports, perhaps
the subject’s email address or a webpage.
You may have e-mail address as a field but this will
enable you to access it.
Hyperlink

A lookup simplifies data entry as you can select
from a drop down box. Here, you select the name
of the GP without having to type it in.
Lookup

Data on its own has no meaning. 16,31,17,04,20,39
is just a series of numbers. Once processed it
becomes information, for example, the data is a
string of candidate numbers and marks.
The candidate numbers can be looked up to find
candidate name. The marks can be looked up in a
table of grade boundaries. So the information
would be:
Robinson, B C Grade
Leighton, M U Grade
Ahmed, M B Grade
Data is input to a computer system and, after
processing, becomes information.
Summary

Data types

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Data types

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