Re: Storing data and code in a Db with LISP-like interface

Neo wrote:
[snip agreement]
>
> Ok, I didn't expect someone familiar with RM/RMDBs/SQL to have such
> difficulties with 'create'.

Some of my difficulties originate from that familiarity. DML's 'insert' would be more innocent-looking. 'Create' is DDL: it changes the strucure of the database - alarm bells! 'Create' can be viewed as a catalog-insert.

[snip agreement]

>>>>>[ person (john) ] how does one determine the name of the relationship via code?
>>>
>>>>There is no [way], because I did not provide a name for this relationship.
>>>
>>>It seems there maybe yet another reason. Prolog may not provide a
>>>method to determine the function given one set of parameter already
>>>specified. Can some experiences Prologer correct me on this?
>>
>>Can you make your statement in a way which is more test-friendly?

Are you stating the same fact in two ways or are these two facts?

> Then ask prolog, what is the relationship between john and person; and
> vice versa, what is the relationship between person and john. You can
> replace john, person, class, instance with other things that make more
> sense to you, for instance:
>
> parent (johnny, john). meaning johnny's parent is john
> child (john, johnny). meaning john's child is johnny

This clearly looks like you are stating the same fact in two ways - so I am going to assume that.

To prevent redundant solutions you can have one of them as ground fact, the other one as rule.

--------------neofam.pro part 1

has_parent(johnny, john).         % meaning johnny's parent is john
has_parent(johnanna, john).       % meaning johanna's parent is john

has_child(Parent, Child) :-
     has_parent(Child, Parent).    % to infer that e.g. john's
                                   % child is johnny

sibling(S1, S2) :-                % bonus :-)
     has_parent(S1, P),
     has_parent(S2, P),
     S1 \= S2.

I had to (for now arbitrarily) choose which one to see as basic and which one as derived. That is a choice often coming up, I don't think it is a prolog-specific one.

> Then when prolog is asked, what is the relationship between john and
> johnny, it should respond similar to "john's son johnny" and vice
> versa.

It would have to know (be told or have the rules to infer) that johnny is male and that male children are sons.

> Here is how to do it in dbd:
>
> (create johnny parent john)
> (create john child johnny)
>
> // Following displays parent.
> (msgbox (& (select verb instance *) (select johnny * john)) )
>
> // Following displays child.
> (msgbox (& (select verb instance *) (select john * johnny)) )
>
> In dbd, one can also represent the relationship between verbs, ie
> parent and child as
>
> (create parent reciprocal child)
> (create child reciprocal parent)

Are these two dbd.things or alternate formulations for one dbd.thing?

> Dbd's Food Judge Example C, relates like and likedBy similar to above,
> thus when using the createWRR (create with reciprocal relationship
> also), and user enters "(createWRR john like tomato1)", db
> automatically creates the reciprocal relationship "(create tomato1
> likedBy john)". There is a query later that uses likedBy to find out
> all the people who like tomato1 via the following query: "(select
> tomato1 likedBy *)". Note the Food Judge Example C is posted in
> response to master Prologer Alvin.
>
>

>>Do we have the same concept of "thing"?

>>I have a hard time seeing a category as a thing.

Yep.

>>>A relationship is just another thing that is represented in the dbd. The following displays "class": (msgbox (and (select verb instance *) (select john * person))). And the following display "instance": (msgbox (and (select verb instance *) (select person * john))). How would one do this in Prolog?
>>
>>Why?

>>>So that the Prolog solution could answer the questions: what is the
>>>relationship between john and person; and what is the relationship
>>>between person and john.
>>
>>I'll re-ask: for what purpose do you need to know it?
>>Which information need are you satisfying/preempting whith it?
>>This would shed some light on what to record.

Nice scenery.
--------------neofam.pro part 2

human(john).    % not needed for the specifically
human(sally).   % stated information needs.
human(martha).
human(ellen).

boy(john).
girl(sally).

has_mom(sally, martha).
has_sister(martha, ellen).

has_boyfriend(sally, john).
has_girlriend(Boy, Girl) :-

     girl(Girl),
     boy(Boy),
     has_boyfriend(Girl, Boy).
--------------------------

Who1 = john
Who2 = sally ;

No

Could you give a more specific situation where the droid would need "thing", "class", "relationship" or "instance"? Received on Fri Apr 28 2006 - 10:36:52 CEST