3

Data, Files and Records

The prime function of a computer is to store information, the later being referred to as “data”. This data can then be manipulated and extracted according to specific instructions. Such instructions are known as computer “programs”.
Data is organized into “files” and a “data base” can consist of one or more files. A file will contain a number of similar “records”and each record is made up of elements called “fields”.


FILE
RECORD
FIELDS


In library applications, a “file” might, for example, be a catalogue. The “record” then becomes each individual entry, eg ISBN, Author, Title, Date, etc.
Fields may be in “fixed or variable” format. A fixed is one of a specific length in terms of characters (a character being a single letter, digit, punctuation, mark, symbol, or space). With fixed fields, the computer is able to calculate which field it is handling at a given time by a count of characters from the beginning of the record. With variable fields, each field may contain a varying number of characters. The length of records and constituent fields will now differ. The beginning and end of each record and each field must therefore be marked by “tags” or “indicators”, which the computer can recognize.
The manner in which a record is organized will depend upon the requirements of the individual cataloguing agency. This organization can be standarized to facilitate the exchange of data between agencies. One very important international standard of this nature is the MARC (Machine Readable Catalogue) format.