> From: Joshua Gargus
> what is it that RDBs *fundamentally* get correct?

People find it easy to understand tabular data and to cross-reference
between tables.  Relational databases contain tabular data.  So people
find relational databases easy to understand compared to the
alternatives.  Other than the uniformity ("everything is either a tuple
or an atomic value"), there's little else to commend them - but that
ease of understanding has been enough, I think.

The rest of the system is optimisation to try to get relatively
efficient use of the machine despite expressing the problem in ways that
are easy for humans to understand.  Oh, and trying to make up for the
*dreadful* query language that IBM inflicted on the world with SQL.  I
learned the principles of relational systems with db++, a very odd
relational system that used a very clean relational algebra where
select, project and join were first-class operations.  It's certainly
helped me cut through the fog of SQL, where the principles are far less
clear!

		- Peter