Path: utzoo!attcan!uunet!lll-winken!lll-tis!daitc!jkrueger
From: jkrueger@daitc.daitc.mil (Jonathan Krueger)
Newsgroups: comp.databases
Subject: Re: SQL = 4GL ???
Keywords: 4GL buzzwords
Message-ID: <161@daitc.daitc.mil>
Date: 22 Aug 88 22:18:17 GMT
References: <24484@bu-cs.BU.EDU> <641@stech.UUCP>
Reply-To: jkrueger@daitc.daitc.mil.UUCP (Jonathan Krueger)
Organization: Defense Applied Information Technology Center, Alexandria VA
Lines: 54

>We've just managed to start an argument here regarding the
>actual definition of 4GL and its relationship to SQL...
>
>IS SQL considered a 4GL?
>and if it isn't .. what is it? ... also as long as I'm 
>asking, what about QUEL, dBASE, and other languages... 
>according to my RTI (Ingres) documentation they call OSL
>a 4GL but not SQL or QUEL... could someone define the 
>term 4GL??

1GL	machine language: toggle switches, modify plugboards,
	binary edit machine instructions

2GL	assembler: mnemonics for instructions, symbols for
	data and control structures, subroutine libraries

3GL	programming languages like C, Pascal, Fortran: portable
	machine-independent programs, portable function libraries,
	more abstract data and control structures

These terms were coined after the fact.  At the time, 3GL's were
called "high level languages" or even "automatic programming systems"!
So if you find such distinctions facile, and don't think them accurate
or useful, great, they're all just generalizations.  At least there's
consensus about what they mean.

But "4GL" has been used before the fact, mostly by marketing types.
Little consensus has developed concerning its use.  For instance, I'd
use the term to mean:

4GL	packages, toolkits, or shells; higher level abstractions
	than 3GL, aimed at safer and more productive programming;
	specialized to certain kinds of programming, such as database
	management, circuit simulation, process control.  Usually
	tries to encapsulate commonly used constructs from 3GL's, for
	instance "where clause" qualification encapsulates iteration.

Therefore, I'd have no problem with calling SQL a 4GL, just as I'd
accept the circuit description language for SPICE.  However, common
vendor use, such as your RTI docs, would use 4GL to mean:

4GL	application generation, aimed at programming for
	non-programmers; automatic generation of a user
	interface from a data dictionary and programmer-specified
	customizations

Which would accept OSL but not SPICE or SQL.  So if you listen to
people selling dbms software, their 4GL will be touted as an addition
to SQL.  The rest of us have fallen into that usage, but would accept
other tools and shells as well, e.g. the Unix shell, SQL, SPICE, KEE.

-- 
Jonathan Krueger  uunet!daitc!jkrueger  jkrueger@daitc.arpa  (703) 998-4777

Inspected by: No. 15