Storing data in tables
Databases store data in tables. Tables are made up of fields and records.
A prison might use a database to keep records of its inmates. A criminal鈥檚 record may contain the following fields:
- first name
- last name
- height
- crime
- release date
A table consists of related records, eg people convicted of a crime, and a record consists of related fields, eg Paul Smith who is 1.8 m, committed a robbery and is being released on 26.01.2015.
Creating a table
To create a table in Microsoft Office Access, use Design view. Start by writing a list of sensible field names, eg 鈥楥rime鈥 would be a better field name than 鈥楢ct of questionable judgement鈥 because 鈥楥rime鈥 is short and to the point.
Data types
Access will automatically choose a field鈥檚 Values, typically letters or numbers. type based on the data entered. For example, if a phone number is entered into a field its data type will be automatically set to 'Number'. Other data types include:
- 'text' 鈥 writing
- 'date/time' 鈥 date or time
- 'currency' 鈥 euro, pound, dollar, etc
- 'autonumber' 鈥 number increases by one each time
- 'yes/no' 鈥 only yes or no can be entered
Setting a primary key
The primary key is a field that contains data that is unique for each record. A car dealership may use a car's registration or number plate as a primary field to set apart two cars of the same colour, make and model.