Use Prolog to get data model paths from language rules?

Question

I want to build a semi-natural language interface for a data warehouse. A simple data model looks for example like this:

Company
- attribute 'name'
- reference to 'Departments'

Department
- attribute 'type'
- reference to 'Employees'

Employee
- attribute 'age'
- attribute 'salary'

And I would like to make queries like so:

ACME employees, Bugs Bunny salary, ACME department types etc.

For input that is not in the grammar, I would call the database and resolve say ACME into Company.

... and turn the queries into paths that my database language will understand:

[Company].departments.employees, [Employee].salary, [Company].departments.type.

I remember using SWI-Prolog way back when to parse English sentences and say if they are correct. Is Prolog still the way to go in this case?

Thanks

@whd thanks! Have gone through a few DCG and 'Prolog as a Database Query Language' tutorials and got my answer. — Radek, Apr 07 '12 at 11:06

CapelliC · Answer 1 · 2019-05-22T15:00:45.767

In SWI-Prolog, there is Chat80 ready to install. I think could be very similar to what you are after, mutatis mutandis.

Just a sample query from the session log (note: was my own old port of chat80 to SWI-Prolog, the pack is presumably more functional, but I haven't tried to run):

what rivers are there ? 

Parse: 0.0168457sec.
whq
   $VAR
      1
   s
      np
         3+plu
         np_head
            int_det(B)
            []
            river
         []
      verb(be,active,pres+fin,[],pos)
      void
      []



Semantics: 0.0170898sec.
answer([B]) :-
   river(B)
 & exists B 
     true

Planning: 0.0sec.
answer([B]) :-
   river(B)
 & exists B 
     true
amazon, amu_darya, amur, brahmaputra, colorado, congo_river, cubango, danube, don, elbe, euphrates, ganges, hwang_ho, indus, irrawaddy, lena, limpopo, mackenzie, mekong, mississippi, murray, niger_river, nile, ob, oder, orange, orinoco, parana, rhine, rhone, rio_grande, salween, senegal_river, tagus, vistula, volga, volta, yangtze, yenisei, yukon and zambesi.

Reply: 0.166992sec.

The logical form required by discourse to answer a query it's the central point of the system. Not really easy to craft from ground!

I read the book Prolog and Natural Language Analysis, F.Pereira, S.Shieber, 1987 (translated in Italian), still my preferred! The english original it's freely available here.

Thanks for the Chat80 reference. Luckily, the scope of the queries I am making is smaller and the language is way simpler. — Radek, Apr 09 '12 at 10:55

score 1 · Accepted Answer · answered Apr 09 '12 at 10:53

Even, better, I now use DCG with embedded Prolog rules.

So, for a model that has classes and attributes like this:

c(company, class(company)) --> [company].
a(company, attribute(name)) --> [name].

I can ask for attributes of a class of a class:

q(q(A,C1,C2)) --> a(T1,A), [of], c(T1,C1)
    ,[of], c(T2,C2), {is_child(T1, T2)}.

And get a tree back as an answer.

score 0 · Answer 3 · answered Apr 07 '12 at 11:08

Have ended up with this example that translates a 'sentence' into a path in the model:

% root classes
class(ceo).

% model relations
attribute_of(age, ceo).
attribute_of(salary, ceo).

% grammar of relations
attribute('age', age).
attribute('salary', salary).
attribute('money', salary).

% answer format
answer([Class, Attribute], Class, Attribute).

% language rules
% query(Attribute,'of',Object, Answer).
query(AttributeQ, 'of', ClassQ, Answer) :-
    db(ClassQ, Class), attribute(AttributeQ, Attribute), attribute_of(Attribute, Class), answer(Answer, Class, Attribute).

% database
db('Bugs Bunny', ceo).

As an example, the following query:

?- query('age','of','Bugs Bunny', Answer).

...gives me:

Answer = [ceo, age].

Use Prolog to get data model paths from language rules?

3 Answers3