Computer files

  • A file can be defined as a collection of related records that give a complete set of information about a certain item or entity. A file can be stored manually in a file cabinet or electronically in computer storage devices.
  • Computerized storage offers a much better way of holding information than the manual filing system which heavily relies on the concept of the file cabinet.

  • Some of the advantages of computerized filing system include:

  1. information takes up much less space than the manual filing
  2. it is much easier to update or modify information
  3. it offers faster access and retrieval of data
  4. It enhances data integrity and reduces duplication
  5. It enhances security of data if proper care is taken to secure it.

Elements of computer file

  • A computer file is made up of three elements: characters, fields and records.
  • Characters
  • A character is the smallest element in a computer file and refers to letter, number or symbol that can be entered, stored and output by a computer. A character is made up of seven or eight bits depending on the character coding scheme used.
  • Field
  • A field is a single character or collection of characters that represents a single piece of data. For example, the student’s admission number is an example of a field.
  • Records
  • A record is a collection of related fields that Represents a single entities, e.g. in a class score sheet, detail of each student in a row such as admission number, name, total marks and position make up a record.

Logical and physical files

  • Computer files are classified as either physical or logical
  • Logical files
  • A computer file is referred to as logical file if it is viewed in terms of what data item it contains and details of what processing operations may be performed on the data items. It does not have implementation specific information like field, data types, size and file type.
  • Physical files
  • As opposed to a logical file, a physical file is viewed in terms of how data is stored on a storage media and how the processing operations are made possible. Physical files have implementation specific details such as characters per field and data type for each field.