Re: Implementation of boolean types.
Date: Sun, 17 Jul 2005 21:06:28 +0200
Message-ID: <dbea7k$c1a$1_at_sunce.iskon.hr>
>
> The expression can be collapsed. Say there are only 3 known values of
> Bonus in the Emp table (out of 10). Then
>
> totalBonus = 1000 + x1 + x2 + 2000 + x3 + 3000 + x5 + x6 + x7 =
> = 6000 + (x1 + x2 + x3 + x5 + x6 + x7) = 6000 + y
>
> An implicit rule is that expressions involving variables can be renamed
> to other variable.
>
Yes .... that's it :-) The variable names/symbol names in a relation are attribute names subscripted by primary keys. For example:
emp.bonus is {1000 EUR, bonus[petar], bonus[paul], 2000 EUR, ... }
Of course, you could change bonus[petar] to x1, bonus[paul] to x2 etc. When we augment RDBMS with this symbolic staff then we need the funcionalnity of equation solving in the engineand then things get really exicting :-)
Geetings,
Drago
P.S.: Notice the "type" of the bonus attribute. Received on Sun Jul 17 2005 - 21:06:28 CEST