Computer Files: It is convenient to store similar information together and this is the idea behind both manual and computer files.
Data Field: The smallest unit of data is the data field. The data field consists of a group of related characters treated as a single entity.
Record: A collection of related data items treated as a single unit is called a record.
File: Records are grouped to form files. A file is a number of related records that are treated as unit representing a particular transaction.
Master File: Master files are perpetual files, i.e. apart from the time of their creation they are never empty. Further, they maintain information that remains constant over a relatively long period of time. When the information changes the master file may be updated. The normal methods of updating are by adding, deleting or editing records in a file.
Transaction File: Transaction files are files in which data prior to the stage of processing is recorded.
The data in transaction records may be collected automatically or may be initially recorded on source documents and later converted to machine-readable format.