A transaction file is a data file in which transaction records are stored which relate to entries in a master file. These kinds of files serve to isolate regular transaction activity from the master file information while allowing a database to tie the two together through a key reference. This key reference is usually a single entry common to both groups of records such as an account number, employee or client name, or purchase order. This allows database operators to keep master files relatively small while having access to full transaction histories for audit trails or reporting.
Company databases can contain extremely large amounts of information which typically consist of the individual details of clients, suppliers, and employees and records of recurring events pertaining to each. Often these databases are split up into master and transaction files. The master file contains individual specific details such as names, company contacts, addresses, email lists, and specific products or services particular to the individual or company. The transaction file contains sales or purchase transactions, calendar events, or employee details such as leave, disciplinary action, or career progression reports.
These blocks of transaction data include a key entry which is a piece of information common to both master and transaction files. This may be an account number, a contact name, employee identification number, or financial details such as purchase orders or invoice numbers. The key entry is a unique identifier which the database uses to tie the transaction entries to their corresponding master file records. Any query or search for a particular master file transactions will then isolate either the entire group of entries for that record or any one specific entry depending on how specific the key is.
Maintaining separate master and transaction file records allows the master file to be kept at a manageable size and dedicated to entity specific entries only. In applications in which users store transaction records off-site or on archive servers, separating them from the master file also makes archiving a lot easier. Keeping a dedicated transaction file also makes for easy and effective auditing. This file may also serve as a diagnostic or planning aid with many databases featuring extensive reporting functions based on its contents. This type of split file arrangement is often known as a referential file system because the master file “refers” to the transaction file for specific event details.