Re: New to Databases-books on databases

In comp.databases Shane Kershaw <NsopSpramk_at_ozemail.com.au> wrote:
: In article <8e5e34ef.0108062006.78d96854_at_posting.google.com> Kim
: Goldsworthy, gebegb_at_earthlink.net writes:
: What is the meaning of "orthogonal" that C. J. Date keeps mentioning?
:>My collegiate dictionary does not list a definition that seems to :>match what Date is saying.  

: I tend to think of it meaning "at right angles to the current thought" -
: sort of a multi-dimensional space (N>3) concept, but I must say that I
: like mutually independent. The right angles idea was what was thrown at
: me during my degree studies by the various profs, so it just may be an
: environmental thing (the meaning I use) rahter the rue meaning - it made
: sense at the time, and still does.

FOLDOC sez: Orthogonal:
'Mutually independent; well separated; sometimes, irrelevant to. Used in a generalisation of its mathematical meaning to describe sets of primitives or capabilities that, like a vector basis in geometry, span the entire "capability space" of the system and are in some sense non-overlapping or mutually independent.

In logic, the set of operators "not" and "or" is orthogonal, but the set "nand", "or", and "not" is not (because any one of these can be expressed in terms of the others).'

Keep an eye on the phrase: 'like a vector basis'. That's the point.

: Thoughts from the desert

Thoughts from the fog. Received on Fri Aug 10 2001 - 17:45:34 CEST