Hello Vadim, Marshall and others,
The discussion seems to warrant it's own thread, so here goes.
There seems to be some disagreement on what algebra we are studying.
So let's discuss this first. It is important this get's fixed, because

Lately, I came to put a version of Microsoft Vista on my desktop.  As
I am accustomed to with Microsoft OS's, I am bracing for the impact of
how much extra RAM will be consumed when adopting a new generation of
OS to make it function prperly.  For Vista, I found out it is a

I'm a programmer with 10 years experience experience and I'm about to
(try to) implement my own in-memory database. I have worked with
databases on Solaris for the past 4 years or so.
I want to implement my own in-memory database. However, I lack

One of the most frequent misconception I face when working is about
how concatenation became a synonym for addition of attributes.
Lately, I have had the following example in a board...
COL1       COL2

Given a relation R(x,y) with domains x={0,1,2}, y={'a','b'} we know
from classic predicate theory that the expression
R(x=0, y='a')
evaluates to true or false. Here is how we establish this siumple fact

Symmetric difference identity
(A \ B) \/ (B \ A) = (A \/ B) \ (B /\ A)
holds in relational lattice.

Okay, a while back we were talking about writing constraints
in a language with aspects of the relational calculus, specifically
the existential and universal quantifiers. The point was made
that that's unnecessary; the calculus is no more expressive

Reposting with more clarification (as Jan asked).
Suppose I have a BNFgrammar and a source text parsed into a tree. How
would I query an
identifier declaration?

Wanted to get this groups opinion on my issue.  I started a thread @
microsoft.public.sqlserver.server .........  Can you all take a look &
offer any advice?
http://groups.google.com/group/microsoft.public.sqlserver.server/browse_thread/t
hread/46126ff8c5af502c/f3cdb66023ee17ac

Copies of my book "Analytics & OLAP in SQL" have pages 13-44  missing
and pages 61-92 printed twice.  Please contact Morgan-Kaufmann  or
your book dealer for replacements.  I cannot do anything (Remember the
movie THE PRODUCERS?  "Don't kill us [the producers]!! Kill the

I am interested in informed feedback on the use of Constraints, Primary Keys
and Unique.
The following SQL statement creates a Bands tables for a database of
bookings Bands into Venues, where the rule of the business is that only band

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background preferred]
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I have a table T with -- let's say -- a million+ records.  The
application allows logical deletion of a small fraction of these
records.  (Un-deletion of deleted records is allowed if you have admin
privs via a Priveleges table.)

There was a discussion on OOAD/UML at my workplace and the this was
the facilitator's comments. It was difficult to digest but this is
what was said/done:
We have a business application to develop. We read the problem

RL complement is well-defined. It is roughly the complement
of the rows and the complement of the columns.
1. !A has all the columns that aren't in A
  In other words: