A computer, in its most simplified definition, is nothing more than a device that stores, processes, communicates, and manipulates data. Data is at the heart of every computer program, every web site, and even every video game.
The computer has revolutionized modern life by enabling a level of speed and accuracy to handling information that has never before been possible. Computers accomplish this quite simply by following a set of instructions called code.
A flat file is a static document, spreadsheet, or textual record that typically contains data that is not structurally related. Flat files are called so because there is little that can be accomplished with the information contained in them other than reading, storing, and sending.
Flat files are typically basic data sets that are used for configuration data storage for applications and programs. The average computer user will not typically see them much. There are basic address book-like examples of a flat file that can be used, but modern users typically desire a more robust and sophisticated method of calling up their information than to rely on the limited capability of a flat file structure.
Flat files are commonly used by and found in database management systems, typically belonging in and organized into flat file databases. A flat file database is really nothing more than an organization criterion assigned to a sample set of flat files.
Programmers probably use flat files and flat file databases much more often than the average computer when constructing applications in database management systems such as MySQL, a popular DBS that supports multiple programming languages.
Flat files are also commonly used by website developers for use within languages they utilize such as PHP or ASP.
It has been noted that flat files, since they are simple data files, take up much less space than structured files. However, the utility reading flat files must be rather sophisticated in that it will need to know what to do with the flat file once it has been accessed.