4G Langages

Often abbreviated 4GL, fourth-generation languages are programming languages closer to human languages than typical high-level programming languages. Most 4GLs are used to access databases. For example, a typical 4GL command is

SELECT FIELD FROM TABLE INTO STRUCTURE

The other four generations of computer languages are

first generation: machine language
second generation: assembly language
third generation: high-level programming languages, such as C, C++, and Java.
fifth generation: languages used for artificial intelligence and neural networks.

A programming languages are derived from computer's machine language. Machine languages consist entirely of numbers and are almost impossible for humans to read and write. Assembly languages have the same structure and set of commands as machine languages, but they enable a programmer to use names instead of numbers.
Each type of CPU has its own machine language and assembly language, so an assembly language program written for one type of CPU won't run on another. In the early days of programming, all programs were written in assembly language. Now, most programs are written in a high-level language such as FORTRAN or C. Programmers still use assembly language when speed is essential or when they need to perform an operation that isn't possible in a high-level language.


Fourth-generation languages are smart way of communicating with computers as much like the processes executing intelligent algorithms. Certain tasks can be performed faster and more accurately by traditionally programmed computers than by human beings, particularly numerical computation and the storage, retrieval, and sorting of large quantities of information. Some of the features of a 4 G language are exception handling, Object Orientation in programming. Object-Relation Mapping, garbage collection and dynamic binding.

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