Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!usc!elroy.jpl.nasa.gov!hacgate!ashtate!dbase!awd
From: awd@dbase.A-T.COM (Alastair Dallas)
Newsgroups: comp.databases
Subject: Re: How good is DBASE IV (is it relational)
Summary: dBASE is relational
Message-ID: <455@dbase.A-T.COM>
Date: 6 Mar 90 17:41:40 GMT
References: <1990Mar5.200741.12539@wash08.uucp>
Distribution: usa
Organization: Ashton Tate Development Center Glendale, Calif.
Lines: 30

In article <1990Mar5.200741.12539@wash08.uucp>, crw90@wash08.uucp writes:
> 	How does DBASE IV rate as a true relational database?  Does
> it have true data integrity checks (cannot add a records to a child 
> table unless a referenced record exists in the parent table, etc.)?

By my definition, dBASE is relational--it supports relational algebra of
various kinds on normalized tables of data.  It certainly isn't hierarchical.
As I take your meaning, however, "true relational" does not describe
dBASE.  Referential integrity, in particular, is the responsibility of
the programmer and can be defeated by a determined interloper (using DOS).
The check you refer to (constraint based on lookup in a child table) can
easily be programmed using the dBASE language.

> Can someone suggest some other PC based database products that are
> truly relational?  Please let me know.

SQL systems tend to be more "truly relational," and I've heard good things
about Borland's QBE-based Paradox.  But over the years dBASE has been
phenomenonally successful because it allows "true relational" but doesn't
hold your hand.  Like the C language vs. Pascal, I suppose--you get raw
power but with it comes responsibility (I ought to set this to music).

Hope it helps.

/alastair/

> Potential vendors are welcome to respond!!

Thanks, I did.
Standard Disclaimer> These are my opinions, not Ashton-Tate's.