Dictionary of Computers - file updating

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Reviewing and altering the records in a file to ensure that the information they contain is accurate and up-to-date. Three basic processes are involved: adding new records, deleting existing records, and amending existing records.

The updating of a direct-access file is a continuous process because records can be accessed individually and changed at any time. This type of updating is typical of large interactive database systems, such as airline ticket-booking systems. Each time a ticket is booked, files are immediately updated so that double booking is impossible.

In large commercial applications, however, millions of customer records may be held in a large sequentially ordered file, called the master file. Each time the records in the master file are to be updated (for example, when quarterly bills are being drawn up), a transaction file must be prepared. This will contain all the additions, deletions, and amendments required to update the master file. The transaction file is sorted into the same order as the master file, and then the computer reads both files and produces a new updated generation of the master file, which will be stored until the next file updating takes place.

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