Usage of database consist of
request and transportation of results into visualizer.
We all are looped on Internet, thus visualizer should be remoted.
The most general format for data is XML.
We also need to choose transport protocol:
the most widespread is HTTP.
SQL could send data so.
Now SQL don't make this, thus we need one more language (php,etc).
It's very, very bad for un-experienced user.
We dream, that we simplify SQL by reject of this feature,
but really we only carry un-triviality into other language.
Un-triviality is saved !
But in addition to un-triviality, you have place of dock
between SQL and other language.
I offer the following way:
http://sql40.by.ru/site/sql40/en/author/introduction_eng.htm
http://sql40.by.ru/site/sql40/en/author/determination_eng.htm
Representation of data as tree (instead of as matrix) is not aim itself,
it's sideline-result.