Page 211 - DCAP104_EXPOSURE_TO_COMPUTER_DISCPLINES

Exposure to Computer Disciplines

Notes A manager can say the same thing any number of ways. For example, “Get me tennis racket
sales for January” works just as well as “I want January tennis racket revenues.” Such a request
may contain misspelled words, lack articles and verbs, and even use slang. The natural language
translates human instructions-bad grammar, slang, and all-into code the computer understands.
If it is not sure what the user has in mind, it politely asks for further explanation.
Natural languages are sometimes referred to as knowledge-based languages, because natural
languages are used to interact with a base of knowledge on some subject. The use of a natural
language to access a knowledge base is called a knowledge-based system.
Consider this request that could be given in the 4GL Focus: “SUM ORDERS BY DATE BY
REGION.” If we alter the request and, still in Focus, say something like “Give me the dates and
the regions after you’ve added up the orders,” the computer will spit back the user-friendly
version of “You’ve got to be kidding” and give up. But some natural languages can handle
such a request. Users can relax the structure of their requests and increase the freedom of their
interaction with the data.
Here is a typical natural language request:
REPORT THE BASE SALARY, COMMISSIONS AND YEARS OF
SERVICE BROKEN DOWN BY STATE AND CITY FOR SALESCLERKS
IN NEW JERSEY AND MASSACHUSETTS.

10.2.7 Choosing a Language

How do you choose the language with which to write your program?

There are several possibilities:
 In a work environment, your manager may decree that everyone on your project will use
a certain language.
 You may use a certain language, particularly in a business environment, based on the need
to interface with other programs; if two programs are to work together, it is easiest if they
are written in the same language.
 You may choose a language based on its suitability for the task. For example, a business
program that handles large files may be best written in the business language COBOL.
 If a program is to be run on different computers, it must be written in a language that is
portable-suitable on each type of computer-so that the program need be written only once.

 You may be limited by the availability of the language. Not all languages are available in
all installations or on all computers.

 The language may be limited to the expertise of the programmer; that is, the program may
have to be written in a language the available programmer knows.
 Perhaps the simplest reason, one that applies to many amateur programmers, is that they
know the language called BASIC because it came with-or was inexpensively purchased
with-their personal computers.

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