• There are numerous types of files used for storing data needed for processing, reference or back up. The main common types of processing files include

• Master files,
• Transaction,
• Reference,
• Backup, report and
• Sort file.

1. Master file

• A master file is the main that contains relatively permanent records about particular items or entries. For example a customer file will contain details of a customer such as customer ID, name and contact address.

1. Transaction (movement) file

A transaction file is used to hold data during transaction processing. The file is later used to update the master file and audit daily, weekly or monthly transactions. For example in a busy supermarket, daily sales are recorded on a transaction file and later used to update the stock file. The file is also used by the management to check on the daily or periodic transactions.

Reference file

A reference file is mainly used for reference or look-up purposes. Look-up information is that information that is stored in a separate file but is required during processing. For example, in a point of sale terminal, the item code entered either manually or using a barcode reader looks up the item description and price from a reference file stored on a storage device.

Backup file

A backup files is used to hold copies (backups) of data or information from the computers fixed storage (hard disk). Since a file held on the hard disk may be corrupted, lost or changed accidentally, it is necessary to keep copies of the recently updated files. Incase of the hard disk failure, a backup file can be used to reconstruct the original file.

Report file

Used to store relatively permanent records extracted from the master file or generated after processing. For example you may obtain a stock levels report generated from an inventory system while a copy of the report will be stored in the report file.
Sort file
It stores data which is arranged in a particular order.

• Used mainly where data is to be processed sequentially. In sequential processing, data or records are first sorted and held on a magnetic tape before updating the master file.