Showing posts with label Data-Organization. Show all posts
Showing posts with label Data-Organization. Show all posts

Data Organization

It has been mentioned earlier that in a computer system, the data that is input gets converted into information. We also identified the need for external storage media on which data can be stored for future use.

In our day-to-day lives, we store information in the form of files, be it our telephone directory, or the record of our monthly expenditure. The medium that is used in this type of manual storage is usually paper or other such physical media.

Similarly, information is also stored on the computer in the form of files, but the media is either external storage or internal storage. A computer may have the following types of files on its storage media:

  • Text files
  • Data files
  • Graphic files

Types of Files

Types of Files

Text Storage on a Storage Media

Example of a Text File

Example of a Text File

Any kind of text information, be it letters, documents or memorandums, is stored on the computer in the form of a file, which may be broadly classified as a text file. An example of a text file is shown in Figure.

Data Storage on a Storage Media

Manual Data File

A Manual Data File

Let us now look at how a company manually stores its data. In a manual system, data is stored in the form of a file. A manual file may contain the particulars of each employee in a company (refer Figure).

The manual employee file of a company has several cards, each with the details of one employee. The data to be used in a computer is also stored on a storage media i.e. the floppy disk or hard disk, in the form of a data file. However, a computer data file does not look like a manual data file. Data in a computer file is organized in a different manner (refer Figure).

Computer Data File

A Computer Data File

where

DESIG = designation

DEPT = department

AGE = age of the employee.

In a computer file, the particulars of each employee are contained in a single line. This is referred to as a record. For example, the complete data about employee ANN MURRAY, regarding his designation, department and age, is one record. Thus, a computer file is more compact than a manual file.

Each piece of data in the record is called a field. A field has two components—the field name and the field content (refer Figure). NAME, DESIG, DEPT and AGE are field names. Each record in the file contains these four fields. The field contents are JOHN BROWN, MARY MILLER, CONSULTANT, HRD, 52, etc. The contents of a field usually differ from record to record. You will recall that a character is any alphabet, numeral or symbol, such as %, *, etc. Each field comprises a number of characters. To sum it up, a field comprises several related characters, various related fields make up a record and many such records make up a file (refer Figure). Fields in the records have names.

Graphic Storage on a Storage Media

Example of a Graphic File

Example of a Graphic File

The computer is also capable of storing pictures, moving videos, sketches and other forms of visual information. This type of information is stored in the form of files that may be broadly classified as graphic files. An example of a graphic file is shown in Figure.