[Zope3-dev] catalog 'all documents' abstraction

[Craeg Strong]

Hello:
 
Potentially stupid question: is a query that spans multiple catalogs 
analogous to a relational query that spans multiple tables?

A relational query that spans multiple tables is analyzed by the query 
optimizer to make maximal use of indices.
One can also optionally pass in "hints" to assist the optimizer.
Do those abstractions make sense here?

--Craeg