Introduction to Database Technology

There are two main types of resources. Resources of an organization can be categorized as follows.


Physical Resources

  • People and Money
  • Material and Equipment

Conceptual Resources

  • Data
  • Information


As the operations grow in an organization it becomes difficult to manage the physical resources by observation. Therefore the managers are forced to rely on the conceptual resources. Information is a major corporate resource and must be managed using the principles that are used to manage other physical resources such as people and money.



System Types

There are two types of systems.


1. File Oriented System



The traditional approach to information system design focuses on the data processing needs of individual departments in an organization without considering the organization as a whole. Each computer application is typically designed with its own set of data files and application programs to meet the information requirements of a particular department or a user group.


2. Database Systems



An information system that uses the database instead of data files. It consists of a Database, Database Management System, Data dictionary, appropriate Hardware, Software, and people. Database systems can be designed to store large data collection and centralized data structure. So it supports the overcomes the limitations of the file-oriented system.



Comparison of File Processing System with Database Systems


Traditional File Approach Database Approach
Use separate data files for each application All applications share a pool of related and integrated data
High Data Redundancy  Minimal Data Redundancy 
Data inconsistency Data Consistency
Data not shareable Data shareable
Data dependence Data independence
There is no centralized control for overall data in different files There is a centralized control for overall data in the database
Data Isolation Data Integration
Difficult to access Easy to access



The disadvantage of having a database

  • Complexity and size
  • Cost of DBMS and additional hardware costs
  • Performance problem
  • Higher impact of a failure 



Components of a database system

There are four main components of the Database system. Such as


1. Hardware


In a database, there are set of physical devices resides. It consists of one or additional computers, disk drives, printers, connecting cables and other auxiliary and connecting hardware.


2. Software


There is two type of database software.


  • General purpose database management software

           General purpose database system usually called the database management system. DBMS is system package that allows users to create and maintain an information database and also it gives the user to produce controlled access to this database.


  • Application software

          DBMS facilities manipulate the database and that is used by Application Software to achieve a specific business function. Application software is generally written using standard programming languages or it may be written in a fourth generation language. These programs utilize the command language of the DBMS and make use of the information contained in the data dictionary.


3. People


Two different types of people (users and practitioners) are concerned with the database.


  • User

          Who needs information from the database to carry out their primary business responsibility

          eg: executive managers staff clerical personnel


  • Practitioners

          People responsible for the database system and its associated application software.

          eg: database administrator, analysts, programmers, database and system designers, information systems managers.


4. Data


A database must contain correct and valid data to provide the right information to the right people at the right time perform business tasks.



Functions of DBMS

1. Data Security


The database is a valuable resource needing protection. The DBMS provides database security by limiting access to the database to authorized personnel. Authorized users will generally be restricted to the particular data they can access and whether they can update it. Access is often controlled by password and by the data views, which are definitions of restricted portions of the database.


2. Data Integrity


The integrity and consistency of the database are protected via constraints on values that data items can have and by backup and recovery capabilities provided by the DBMS. Data constraint definitions are maintained in the dictionary.


3. Backup and Recovery


Supported by software that automatically logs changes to the database and provides a means of recovering the current state of the database in case of system failure.


4. Concurrent Data Access


One of the chief functions of the DBMS is to support the access, retrieval, and update of data in the database. The DBMS provides the physical mechanisms allowing multiple users to access a variety of related data quickly and efficiently.


5. User-Oriented Data Manipulation


DBMS provides user-oriented data manipulation tools. Easy-to-use query languages allow users to formulate queries and request one-time reports directly from the database. Often query languages will contain facilities to format the results of queries as reports.


6. Application Development


The DBMS commonly provides significant assistance to the application programmer. Tools for the screen, menu and report generation, application generators, compilers, data and view definition facilities.



Database applications

1. Personal Computer Databases


Design to support one user with a stand-alone PC. Eg: a salesperson keeping track of his customer information with contact details.


2. Workgroup Databases


A relatively small group (less than 25 people), who are collaborating on the same project or application. Eg: a software development team maintaining a list of software objects.


3. Department Databases


A department is a functional unit of an organization. It is larger than a workgroup. Department databases are designed to support the various functions and activities of one department. Eg: a personal database that is designed to track data concerning employees, jobs, skills and job assignments.


4. Enterprise Databases


An enterprise is one whose scope is the entire organization or enterprise. Such databases are intended to support organization-wide operations and decision making. Eg: a large healthcare organization that operates a group of medical centers. An enterprise database does support information needs from many departments. The most important type of enterprise database is called a data warehouse.



What is Next?

In the next lesson, you will learn the Relational Data Model of the Database system.

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