Re: Use of the term "hierarchy"

Marshall Spight wrote:

> Kenneth Downs wrote:
>>
>> SELECT *.employee
>> WHERE project_start < '2005-11-15'
>>
>> the the table-column-oriented system infers that you mean to pull and
>> UNION the results from all tables having columns employee code and
>> project_start?
>
> The concern I have with this idea is that is has so much
> in the way of non-local effects. One is pulling in data
> from essentially the entire namespace. It's not clear to
> me that one wants to have the requirement that the
> namespace be fully unified; that every "employee" attribute
> has to mean the same thing. Scope is a good thing.
>
> Also a non-local effect: the creation of a new table with
> the appropriately-named attributes changes the meaning
> of this query. It's essentially implicitly dependent on the
> entire schema. That's hard to control.
>
>

It seems the whole point of an invented table-column-oriented query is to
search in a wider scope, no? If you don't want that then narrow the scope:

Select *.employee
FROM (table1, table2, table)
WHERE project_start < '2005-11-15'

When you have completely disambiguated your query you are back to
conventional SQL.

--
Kenneth Downs
Secure Data Software, Inc.
(Ken)nneth@(Sec)ure(Dat)a(.com)
.