What is Fourth Generation Language (4GL)

Each programming language generations provides a higher level of abstraction of the internal computer hardware details. This tutorial is about fourth-generation computer programming language.

What is fourth-generation language?

Fourth-generation language is a non-procedural language which means that the programmer defines what has to be done (i.e., what output should be produced) instead of how the task is to be completed. 


It means that you do not need to follow a rigorous command syntax to use them. It is also known as a very high-level language. Non-procedural languages such as SQL, Oracle, postscript, Informix 4GL are considered as fourth-generation languages.

This type of language allows the user to define "what is required" rather than "how it is to be done". These are designed to reduce the overall time, effort, and cost of software development. 


It is common in database applications as query language and data manipulating language, report generators. They let users and programmers to interrogate and reach computer databases using statements that resemble natural languages.

It is typically database-oriented and provides less programming capabilities. It is used for processing large volumes of data than previous generation languages. 

It consists of English words and phrases. For instance: FIND ALL RECORDS WHERE NAME IS 'LEARNING MANIA'.

Fourth-generation language is close to natural language. It is closer to the domain, further from the machine. It is application-specific. It is a machine-independent programming language. 

Some 4GLs are aimed at the end-user and comfort of use is then could be defined as very high-level languages and is designed for use by professional computer experts. 

Fourth-generation language needs approximately one-tenth of the number of statements than that of high-level languages needed to achieve the same results. Non-computer professionals can develop software.

The main objective of 4GL is to cut down on development and maintenance time. 4GL is ORACLE, it offers a number of tools like SQL*CLC, SQL*FORMS, SQL*REPORT, SQL*PLUS, etc.

A 4GL usually includes a utility software (tool) that interacts with the database management system  (DBMS) software to store, manage, manipulate and retrieve data that are needed to satisfy user requirements for information.



Examples of fourth-generation language are Query language (SQL), Report Programmer Generators (RPG by IBM) created for punched card machines, Applications generators, MATLAB, minicomputer applications like PowerBuilder, FOCUS, Infotrive-4GL, Progress 4GL, etc. 

The fourth-generation computer programming language is easy to learn and debug. It can be used by professional and non-technical users.

Advantages of fourth-generation languages

1. Programming productivity is increased.

2. One line of fourth-generation language code is equivalent to several lines of third-generation language code.

3. System development is faster.

4. Programming maintenance is easier.

5. End-user can often develop their own applications.

6. Programs developed in fourth-generation language are more portable than others.




Disadvantages of fourth-generation languages

1. The programs developed in the fourth-generation language are executed at a slower speed by the CPU.

2. The programs developed in these programming languages require more memory space of the computer system.


Main domains and families of 4GL

  1. Database queries
  2. Report generators
  3. Data manipulations
  4. Analysis and reporting
  5. Screen painters and generators
  6. GUI creators
  7. Mathematical optimizations
  8. Web development

Types of 4GL

  1. Codeless programming
  2. Report generator programming language
  3. Form generators
  4. Self generator system
  5. Data management
  6. 4GLs have integrated tools that allow easy specification of all information.

History and Development of 4GL

In 1982: Fourth-generation computer programming languages are referred to as non-procedural programming language and high-level specification languages.

A system called MAPPER is included in the early fourth-generation computer programming language. 72 length characters punched card is used for 8-byte sequencing in fourth-generation programming languages. An example of "black box" processing. 

Third generation computer programming languages were seen as error-prone and slow. Since a huge amount of lines of codes were there in the third programming languages, it was hard to understand and use for people having no training.

That's why the fourth-generation computer programming language was added to aid in fast and error-free app development. 



Reference   >>   Britannica,  Techopedia,  Columbia,  Wikipedia
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