ORA-DM-161-E: the data model is not a tree; it permits trees as values

SECTION 2.3: node identity

It says "The data model is a node-labeled, directed graph, in which 
each node has a unique identity."  What about atomic values?
I don't know whether they have identity or not, but I do know 
that they are not "nodes".  In addition, if "the data model...is a 
graph", why not provide us with a diagram of it?

Of course, the reason you cannot present the specific graph is
because there is no specific graph.
This highlights that the data model is an abstraction,
a rich framework that permits many kinds of values, among 
them being trees.  

I think what you mean is "An instance of the data model may contain
node-labeled, directed graphs, in which each node has a unique 
identity."  I am using "instance of the data model" as my 
preferred term for "the complete assemblage of all values 
available during the evaluation of an XQuery or XPath expression".

- Steve B.

Received on Tuesday, 17 February 2004 13:15:49 UTC