Re: [ontolog-forum] Ontologies, knowledge model, knowledge base

[John F Sowa <sowa@xxxxxxxxxxx>]

On 8/10/2012 4:51 PM, Rich Cooper wrote:
> The reason it is important to store rules as well as facts in the
> database is that such architecture makes it very easy to store a table
> of context IDs and relate them to which rules and facts apply to each
> context ID.  Searching for contexts becomes very manageable with that
> method.    (01)

But you need to do much more than storing and finding rules in order
to make a DB into a deductive DB.  The critical task is to make the
deductive component a natural extension of the query component.    (02)

In SQL, for example, a view V uses a WHERE-clause to define
a *virtual* relation that accesses some logical combination of
other relations (which may be stored and/or virtual relations).    (03)

To an SQL user, V looks like an ordinary relation.  But any use of V
will trigger a backward-chaining deduction that is similar to what
happens in a rule-based language like Prolog.    (04)

SQL implementations use a method of storing and indexing their
relations, either stored or virtual.  But that method is separate
from the methods for storing data.  If you store a view as data
in the DB, it will never get used as a view.    (05)

John    (06)

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