Fourth Generation Languages (4GL's) - Overview

Late 1970's - Languages & Tools to develop applications significantly faster than 3GL's

The term 4GL coined by Nigel Read & Douglas Harmon (Article in Datamation 1981). Previously these types of products were termed 'high-productivity tools'.

Essentially a fourth generation language is a tool that enables you to develop an application an order of magnitude faster than a third generation language, and will cross many parts of the system development cycle.

Fourth generation languages are often best described as

"Neither a third or a fifth generation language",

Hence may encompass;

Application builders
Very high level languages, including Visual Basic for Applications (MS-Excel) and Macro languages.
Decision support tools
Program generators (not just for database applications).
Database-oriented tools

These tools are designed to be used by

Programmer
DP Professional
End-user

Characteristics

Variety of Languages
Variety of Tools
Querying Languages
Decision Support Tools
English-like key words
Generally portable across a range of machines
More "user friendly", some suited to use by non-professional
Translated by compiler, interpreter or both, or uses code generation techniques
Many languages specific types of problem

Non-procedural element central to this generation (specify what has to be accomplished rather than how)