Computer Languages


A natural language is a medium of communication between human being. The natural languages such as Hindi, Punjabi, English, etc. is used to communicate with each other our ideas and emotions. Similarly, a computer language is a means of communication used to communicate between people and the computer. With the help of a computer language, a programmer tells a computer what he wants it to do. All natural languages use a standard set of symbols for the purpose of communication. These symbols are understood by everyone using that language. We normally call this set of symbols the vocabulary of that particular language. For example, the words we use in English are the symbols of English language that make up its vocabulary. Each word has definite meaning which can be looked up in a dictionary. In a similar manner, all computer languages have a vocabulary of their own. Each symbol of the vocabulary has definite unambiguous meaning which can be looked up in the manual meant for that language. Hence, each symbol of a computer language is used to tell the computer to do a particular job. The main difference between natural language and computer language is that natural languages have a large vocabulary but most computer languages use a very limited or restricted vocabulary. Hence, each and every problem to be solved by a computer has to be broken down into discrete (simple and separate), logical steps which basically comprise off our fundamental operations.

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Computer Software and Types of Software


Program or a set of programs is known as Software. Now, What is program? Program is a instruction or set of instructions. So, we can say Computer Programs, namely, the list of  instructions to be executed by a computer are known as the software of a computer. The electronic circuits used in building the computer that executes the software is known as hardware of a computer.   It refers to the physical devices of a computer system, such as Input devices, storage devices, processing unit, control unit , and output devices. A hardware is linked together with software to form a effective working unit that is a computer system.  To take analogy, a home television set bought from a shop is hardware; the various entertainment programs transmitted from the television station are its software. It is immediately evident that hardware is necessary but software is vital. What is the use of a home television set if the programs not transmitted by television station. Another important point brought out by this analogy is that software production is difficult and expensive. Hardware is one-time expense whereas software is a recurring expense.

Thus, there is a special relationship between hardware and software. Both are complementary to each other. Hardware is nothing without software and vice-versa.  By very simple example, these two can be described as both a notebook and a pen are hardware and the written material on notebook is software.

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What is Computer?

The word computer means to compute or to calculate. So a computer is normally considered to be a calculating device.

But, more than 85% of the work done by computer today is of non-mathematical. Hence, a computer may be defined as a device that operates upon data or information. So computer can be defined as a machine in which we can

  • Store data or information,
  • Process data or information,
  • Retrieve data or information

With our requirements

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Management Information System : An Overview

As we discussed in last lectures about System, System Analysis and Design and System Analysis Tools. Now our topic of discussion is Information Systems. Lets Start

Management Information System deals with the systems which produce information for the management at different levels for their proper functioning. Although it is not absolutely essential for MIS, yet it is the computer which has made a reality of the fundamental concepts of MIS. Its assets are speed, accuracy, consistency and the ability to handle large volumes of data. It however lacks judgement for which the human beings can complement it. The general term system, is more specifically applicable to the information systems, are going to be of our main interest. Thus the term MIS may be defined as an integrated man-machine system in producing information to support the operations, management planning & control and decision making functions in an organisation.

Man and machine are thus complimentary to each other and the question really is to what extent computers should be employed. Before we begin the detailed discussion on the various factors to be analysed for the design of a detailed MIS, it will be worthwhile to have a look at the computer technology as it has changed over the last few years which has affected the very design of MIS.


The word data is the plural of datum, which means fact. Data, then, are facts, the raw material of information. Data are represented by symbols, but they are not information except in a limited sense. As used in data processing, information is data arranged in an order and form useful to the people who receive it. However, information is relevant knowledge, produced as the output of data processing operations and acquired by people to enhance understanding and to achieve specific purpose. Figure illustrate the differences between data and information.

Data Vs. Information

           Data (Input)                                         Information (After Processing)


Information is one of the most vital tools for the management. Modern industrial society is faced with Information Explosion. Information has been regarded as an important resource since companies spend major chunk of their costs towards collecting, processing and transmitting the information to various levels of management for their proper.

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System Analyst and Analysis Tools


As per our discussion in last lecture that each system has certain interacting elements. These elements interact with each other in a certain way so as to produce the required output from the given inputs. As we are dealing with man-made systems, so it is man who decides about what should be the inputs for a particular system and in what way different elements should react with each other to produce the desired output. This particular man who analyse (new and existing) and design or redesign the system is called System Analyst. The concept of systems would impose upon the System Analyst to look at the system as a whole.

The primary task of the system analyst is to analyse and design a system which is absolutely new or make a existing system more effective by modifications or by substantial redesign.

The system involved could be economic, political, social institution such as business houses, government agencies, colleges and universities and usually a computer could be considered as an aid for improving the systems operation.

System analyst may be responsible for system analysis, detail design of the computer system and outlining system specification.

The system analyst has two primary objectives

  • Assessment objective
  • Assistance objective

Assessment objective : A system analyst has to observe, understand and evaluate the interactions which routinely occurs as a part of the Job under investigation.

Herein the analyst has to know.

  • What is being done ?
  • Who is doing it ?
  • Why is it being done ?
  • How is it being done ?
  • What are major problems in doing it ?

After the completion of assessment objective, the system analyst offers specific suggestions for improving the efficiency of Job under consideration. He does so by providing assistance.

Assistance Objective : A system analyst is to provide alternative solutions to make the existing system more efficient. For this job, he seeks the help of the computer. At such times he acts like a communication-link between technology and user. Analyst now finds out other ways to deal with the existing problem and also checks the benefits and liabilities associated with these alternative approaches.

Better assessment of problems will provide better assistance, and probably the presence of other kinds of assistance gives the analyst a broader perspective for the assessment.

A system analyst must have good communication with all the people affected. Communication skill of system analyst should be sharp as he depends on others for both information and co-operation. System analyst in facts is an agent of change.

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System Development Life Cycle (SDLC)


To develop a systems, such as Management Information System (MIS), A General Business System, we need to carry out a detailed systems analysis and design activity. For this purpose, we shall have an overview of various stages in this process.

System development follows an iterative process that recycles through each stage and almost all stages overlap each other. This is also termed as the System Life Cycle.


The complete process of systems analysis and design may be considered as consisting of  following phases

  • Recognition of problem (Initial Investigation)
    • What is the problem or opportunity?
  • Feasibility study
    • What are the user’s needs?
    • What are the benefits?
    • How can the problem be redefined?
  • System analysis
    • What must be done to solve the problem?
    • What are the facts?
  • System design
    • How must the problem be solved?
    • What is system flow?
  • System testing
    • How ready are programs for test?
  • Implementation
    • What is the actual operation?
  • Maintenance
    • Should the system be modified?

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System Analysis and Design – I


The term “system” is used in many different ways. Everyone is familiar with such expressions as “Professor Rajneesh has an impossible grading system”. or  “Deepak has a great system for managing friends.” But for computer users, a system is a group of parts that are integrated for the purpose of achieving some objective. The following three characteristics are key:

  1. A group of parts. A system has more then one element. A steering wheel is not a system, but it’s a vital part of a familiar system called an automobile.
  2. Integrated parts. A logical relationship must exist between the parts of a system. Mechanical and electronic system, such as washing machines and video games, have many components that work together.
  3. A common purpose of achieving some objective. The system is designed to accomplish one or more goals. All system elements should be tied together and controlled so that the system goal is achieved.

Since a computer is a group of integrated parts that have the common purpose of performing the operations called for in the program being executed, it qualifies as a system.


The term system is derived from the Greek word systema, which means an organized relationship among functioning units or components. A system exists because it is designed to achieve one or more objectives.  A system is an orderly  grouping of interdependent components linked together according to a plan to achieve a specific objective.  The word component may refer to physical parts, managerial steps or a subsystem in a multi-level structure.

In our daily life,  the word “System”  comes across many a times but seldom the word is understood in its fullest sense. Almost every one of us have heard about Systems such as Education System, Economic System, Office System, Solar System. But what do they imply in the real sense is a  main question.

Systems could be man-made such as education system, office systems etc., or a natural system such as solar system.

We would be dealing with man-made systems. These man-made systems have certain inputs which are processed and the result is certain outputs.

Figure 1 : System

In education system, the main input is new students where they undergo the process of education and the output is a educated student.

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PL/SQL – An Overview

  • An extension to SQL with design features of programming languages  (procedural and object oriented)
  • PL/SQL and Java are both supported as internal host languages within Oracle products.
  • The PL/SQL procedural language was developed by Oracle Corporation in the late 1980s as procedural extension language for SQL and the Oracle relational database.

Following are notable facts about PL/SQL:

  • It is a completely portable, high-performance transaction-processing language.
  • PL/SQL provides a built-in interpreted and OS independent programming environment.

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Structured Query Language – SQL – Basics

SQL, a Structured Query Language is now available with most RDBMS (Relational Database Management System) products as the database language. Which can be used both by end-users and system programmers.

Originally, SQL was called SEQUEL( for Structured English QUEry Language).

SQL is now standard language for commercial relational DBMS.

First reason, a query in relational algebra is written as a sequence of operations that, after execution, produce the required result. Hence, the user must specify how –that is, in what order – to execute the query operations.

On the other hand, the SQL provides a high-level declarative language interface, so the user only specifies what the result is to be, leaving the actual optimization and decision on how to execute the query to the DBMS.

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