Iteration over relations using a database

问题

I'm new to prolog.

Consider the following format:

 carsCompany(Tel_Number,
   Manager,
   Company_Name,
   [new_cars(Car_Name,info(Color,Creator),Date_Creation)],
   [old_cars(Car_Name,info(Color,Creator),Date_Creation)]
   ]).

I would like to create a two argument relation which gets a list of car names and a company and adds them to the company.

update_company([Mazda],Company).

I have the following db example:

 carsCompany(1234,
   Jujiro Matsuda,
   Mazda,
   [new_cars(mazda_3,info(Grey,Person1),26082016)],
   [old_cars(Cosmo,info(Black,Person2),26081927),
   [old_cars(RX-7,info(Black,Person2),26081979),]
   ]).

What I tried to do is to get all the the possible cars using member so I could iterate over the information.

 member(X, [X|Xs]).
 member(X, [Y|Ys]) :- member(X, Ys).

 get_all(New,Old,carsCompany(_,_,_,New_Cars,Old_Cars)) :- member(New,New_Cars), member(Old, Old_Cars).

Although It doesn't really work:

New = [Lecture|_G750],
Old = [Tutorial|_G753] ;
New = [Lecture|_G750],
Old = [_G752, Tutorial|_G756] ;

What is the best way to implement this?

回答1:

Possible solution:

car_company( 1, 1234, person('Jujiro', 'Matsuda'), 'Mazda' ).

production( 1, cars, new, 'Mazda-3', info( gray,  person1 ), 26/08/2016 ).
production( 1, cars, old, 'Cosmo',   info( black, person2 ), 26/08/1927 ).
production( 1, cars, old, 'RX-7',    info( black, person2 ), 26/08/1979 ).

% query:
q :- 
    findall(
        new_car( ID, Model, Color ),
       (  
           car_company( ID, _ , person('Jujiro', 'Matsuda'), 'Mazda' ),
           production( ID, cars, new, Model, info( Color, _ ), _ )
       ),
       Result1
    ),
    writeq( Result1 ),
    findall(
        old_car( ID, Model, Color ),
        (   
            car_company( ID, Phone, person('Jujiro', 'Matsuda'), 'Mazda' ),
            production( ID, cars, old, Model, info( Color, _ ), _ )
        ),
        Result2
    ),                   
    writeq( Result2 ).

来源：https://stackoverflow.com/questions/51047005/iteration-over-relations-using-a-database

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prolog