Re: Poll: Expert user vs. Internals Expert

Neo wrote:

>>The relational model is carefully defined in a well demarked universe of discourse.  Completeness and closure have been demonstrated.  It is, then, over the domain for which it is defined, entirely reasonable.  One who embraces logic would then conclude that anything which contradicts the relational model is unreasonable.

Suppose I want to keep sets of sage and other contributors to c.d.t:

   var sage real relation { name char } key { name } ;

   VAR sage REAL created.
   OK

   sage += relation {
              tuple { name 'Bob' },
              tuple { name 'JayDee' } };

   Inserted 2 tuples.
   OK
   var jerk real relation { name char } key { name } ;

   VAR jerk REAL created.
   OK
   jerk += relation {

              tuple { name 'Neo' } } ;

   Inserted 1 tuple.
   OK

It's a small newsgroup; here are the contributors:

   sage union jerk

   RELATION {name CHAR} {
      TUPLE {name "Bob"},
      TUPLE {name "JayDee"},
      TUPLE {name "Neo"}}

Perhaps we can record who's postings are "on point" and "off point:"

   var state real relation { name char, state char } key { name } ;

   VAR state REAL created.
   OK

   state += relation {
               tuple { name 'Bob', state 'on' },
               tuple { name 'Neo', state 'off' } } ;

   Inserted 2 tuples.
   OK

This expression yields valuable information:

   jerk join state

   RELATION {name CHAR, state CHAR} {

      TUPLE {name "Neo", state "off"}}
   OK Received on Sat May 27 2006 - 03:28:49 CEST