Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!njin!princeton!udel!burdvax!portia!seavey
From: seavey@portia.PRC.Unisys.COM (Beverly Seavey)
Newsgroups: comp.databases
Subject: Re: SQL = 4GL ???
Summary: 4GL, completeness
Message-ID: <7367@burdvax.PRC.Unisys.COM>
Date: 24 Aug 88 13:36:21 GMT
References: <24484@bu-cs.BU.EDU> <641@stech.UUCP> <314@telly.UUCP>
Sender: news@PRC.Unisys.COM
Lines: 15

In article <314@telly.UUCP>, evan@telly.UUCP (Evan Leibovitch) writes:

  >4GL -- specification.  Differs (ideally) from a 3GL in that programmers
	specify what they want done, not how to do it.  That is, a
	true 4GL would be entirely non-procedural and non-algorithmic, 
	accepting high-level goal-oriented specifications as input and 
	producing complete applications as output.


  >Surprisingly, QUEL is a 4GL in this taxonomy, since it is non-procedural.
  >So I guess this taxonomy lacks completeness criteria.

I saw a comment in, I think, Ulmann's new book on knowledge bases,
that giving full power to query languages would make the optimization
of queries undecidable.