Used to store data records. Well-defined data structures that contain related data organized in convenient records of data items. Each data file has two additional types of records: Header record and trailer record. Header records contain file identification information and keep different groups of records in a file. Trailer records contain codes to mark the end of a set of data records.
Categories of Data Files
- Master file: Collection of records pertaining to one of the main subjects of an information system, such as customers, employees, products and vendors.
- Transaction file: Collection of transaction records. The data in transaction files is used to update the master files, which contain the data about the subjects of the organization
- Program files: Used to store programs in different languages provided by different software vendors. These files have different extensions e.g. a program file in ‘C’ Language has an extension.c
- Object code files: Store compiled programs written in a language. These files contain the machine code, e.g. after compilation, C compiler creates a file having extension .obj.
- Executable Files: Store ready to execute programs. These files may have the extension .exe, .com or .bat. These programs can be directly executed from the Command Prompt.
- Unformatted Text Files: Simple files containing simple text. Text files can be created using any text editor or line editor, e.g. text files can be created using Notepad editor provided by MS-Windows.
- Formatted Text Files: Contain formatted text. They also contain some commands and symbols to format the text. These can be created using MS-WORD having extension .doc.
- Other Filers: Work file, Audit file, Backup file