Autonumber

An auto number field increments (adds one) to itself every time a new record is added to the table. It is the ideal field type for a primary key because it never repeats itself, and is therefore unique.

Text

A text field can contain any character, including letters, numbers and punctuation. Certain fields, such as telephone numbers can contain spaces, the “+” sign, and brackets, as well as a place name, for e.g. “Wakefield 303065”. This would be an obvious time to use a text field rather than a number.

Number fields provide an efficient way of storing data that can be expressed in a numerical way, such as how large something is, e.g. length or weight. Number fields can be formatted as:-

• Integers (do not contain a decimal part)
• Currency (contain a currency symbol i.e. £, and two decimal places)
• Decimal (contain a whole number and a decimal part)

This is NOT a field type, but is a method of formatting a number data type (see above)

You can often store data as one of two choices, and the “yes/no” data type is the most efficient way of storing this kind of information.
The yes/no data type does not necessarily have to store yes or no, it can also be used for:-

• True and false (i.e. “Does it have WAP?”)
• Zero and one (binary data type)
• Male or Female