ss instance variables and 
create instances of the class.<P>

Ruby provides weak references but its implementation is so inefficient, that by default it is switched off. 
To enable weak references, set <code>USE_WEAK_REFERENCES=true</code> in dybase.rb.
Also Ruby support delegates: classes which redirect (delegate) methods to some other class. 
With delegate classes there is no need in <code>recursiveLoading</code> method - objects
are loaded on demand. So it is much more convenient then common DyBase model