Hi Alberto:

I think your analogy is a useful one. The LoD is a style rule
for checking whether a program is "normalized" to simplify maintenance.
I was not aware that this connection can be taken further as you suggest.

In summary:

Relational DBMS		Programming

Normalization		Law of Demeter
follow
	many narrow		many small methods
	relations

	requires more joins     requires more navigation
not follow
        large relations		large methods
	maintenance problems    maintenance problems

I noticed that a similar analogy holds for normalizing class graphs.
I use Boyce-Codd Normal Form to normalize a class graph for an oo 
database application.

-- Karl

From mendel@cs.toronto.edu Thu Feb 19 12:31:03 1998
From: Alberto Mendelzon <mendel@cs.toronto.edu>
To: lieber@ccs.neu.edu (Karl Lieberherr)

> 
> Yes, this is very much related to our current work: we are trying to solve
> the Law of Demeter Dilemma: if you follow it, you get lots of tiny
> methods which you have to maintain; 
> if you don't follow it you get a hard to maintain system.

This may be a superficial analogy, but it sounds a lot like normalization
of relational database schemas: if you normalize, you get lots of "narrow"
relations which are easy to maintain, but require joins to answer queries;
if you don't, you get "wide" relations that are hard to update.

-alberto.