Lesson 3: Organizing Data and Information

3.1. Data Management

Without data and the ability to process it, an organisation would not be able to successfully
complete most business activities. In order for the data to be transformed into useful information, it

must be organised in a meaningful way.

3.1.1. The Hierarchy of Data



Data of a book is organised into characters, words, phrases, sentences, paragraphs and chapters.
Similarly data in a database can be organised into fields, records and files that forms a hierarchy.
Data hierarchy begins with the smallest piece of data used by computers (a bit) and progress
through the hierarchy to a database.



Bits can be organized into units called bytes. A byte is typically 8 bits. Each byte represents a
character. Character is the basic building block of data, consisting of letters (A, B, C, …, Z, a, b,
…, z), numeric digits (0, 1, 2, …, 9) or special symbols (., +, -, @, …).

Characters are put together to form a field. A field is typically a name (employee name), number
(salary) or combination of characters (national ID number) that describes an aspect of a business
object (e.g. an employee, a location, a vehicle) or activity (e.g. a sale).

A collection of related data fields is a record. An employee record is a collection of fields about an
employee (i.e. Name, Designation, Department).

A collection of related records is a file (e.g. all employee records – typically known as the
employee file)

Database is a collection of interrelated files (e.g. Employee file, Department file, Payroll file).
A KEY (e.g. Employee, Department and Payroll files can be linked by the Employee ID key)

3.1.2 Data Entities, Attributes, and Keys

Entities, attributes and keys are important database concepts. They are used to describe the
database requirements of an application.

Entity is a generalised class of people (e.g. Employee, Student, Customer), places (e.g. City,
Outlet, Warehouse) or things (e.g. Part, Item, Inventory) for which data is collected, stored and
maintained. A record is an instance of an entity.

Attribute is a characteristic of an entity.

Employee name, Designation are attributes of an employee. Main purpose of an attribute is to
capture the relevant characteristics of entities like employees or customers. The specific value of
an attribute, called a data item, can be found in the fields of the record describing an entity (e.g.
De Silva is data item of the name attribute of an employee entity).

A key is a field or set of fields in a record that is used to identify the record. A primary key is a keythat uniquely identifies the record (e.g. national ID number or name may be used to identify anemployee uniquely).

3.1.3 The Traditional Approach Versus Database Approach

From the beginning of the use of computers to perform business functions, companies have used
the traditional approach to process their functions. In the traditional approach separate files havebeen used for each application. Today it has changed to database approach which uses a unifiedand integrated database for most of the transactions of the company.

Traditional Approach

Manual method of managing data is by recording them on paper (e.g. filling an employee
application form) and putting them in files (e.g. employee file), which are stored using filing
cabinets of the personnel division.

One of the most basic ways to manage data electronically is via computer files, because a
file is a collection of related records associated with a particular application.
The traditional approach to data management use separate data files for each application
programme (e.g. employee file for personnel application, payroll file for payroll application).
For a particular application one or more files were created.



Each division created and managed files required for their applications. Thus data which
were common for several applications appeared in many files (e.g. employee name,
address). This became one of the flaws of the traditional approach to data management
(e.g. employee name and address appeared in employee file, payroll file, benefit file etc.).
Duplication of data in separate files is known as data redundancy.


This caused problems when data had to be developed and coordinated to ensure that each
file was properly updated. As this is difficult to achieve in practice lot of inconsistencies
could occur among data stored in separate files.

Problems of the traditional approach are,

• Data Redundancy

Independent data files included a lot of duplicated data; the same data (Example:
Customer’s name and address) was recorded and stored in several files. This data
redundancy caused problems when data had to be updated, since separate file
maintenance programs had to be developed and coordinated to ensure that each file
was properly updated. Of course, this proved difficult in practice, so a lot of
inconsistency occurred among data stored in separate files.

• Lack of Data Integration

Having data in independent files made it difficult to provide end users with information
for ad hoc requests that required accessing data stored in several different files.
Special computer programs had to be written to retrieve data from each independent
file. This was so difficult, time consuming and costly for some organizations that it was
impossible to provide end users or management with such information. If necessary,
end users had to manually extract the required information from the various reports
produced by each separate application and prepare customized reports for
management.

• Data Dependence

In file processing systems, major components of a system – the organization of files,
their physical locations on storage hardware, and the application software used to
access those files – depended on one another in significant ways. For example,
application programs typically contained references to the specific format of the data
stored in the files they used. Thus, changes in the format and structure of data and
records in a file required that changes be made to all of the programs that used that file.
This program maintenance effort was a major burden of file processing systems. It
proved difficult to do properly, and it resulted in a lot of inconsistency in the data siles.

The Database Approach to Data Management

To overcome the problems of the traditional approach to data management the database
approach is used. In a database approach a pool of related data is shared by multiple
application programs.



To use the database approach to data management, additional software called a
DataBase Management System (DBMS) is required. The DBMS acts as a software
interface between users and databases. This helps users to easily access the data in a
database. Therefore, database management involves the use of database management
software to control how databases are created, integrated and maintained to provide
information needed by end users.