CODEWITHSUNDEEP
prologswi-prolog
nlper
nlper

Reputation: 2407

Flushing the asserts(facts) after each execution

I am using swi-prolog in my python program. It is taking input query from user and creating asserts for it. I have kept this part as gearman worker (like server socket) which keep listening for input query.

  1. 1st query - program generates x numbers of asserts

  2. 2nd query - program generates y numbers of asserts, now program considers (x+y) asserts while processing the query.

and so on.

Is that any way to flush asserts after each query execution? Here is code snippet of process.pro:

Here linkage takes asserts and question is for input query.

question(REND, RULE):-
    linkage(LINK, LEND, REND_NEW),
    (  
        (
            rule_first_question(LINK, REND_NEW) ->
                nb_getval(rule, RULE_NEW),
                nb_getval(rend, REND)
                ; nb_linkval(rule, ''), nb_getval(rule, RULE)
        )
        ;
        (
            rule_third_question(LINK, REND_NEW) ->
                nb_getval(link, LINK_NEW),
                nb_getval(rule, RULE_NEW)
                ; nb_linkval(rule, ''), nb_getval(rule, RULE)
        )
        ;
        (
            rule_four_question(LINK, REND_NEW) ->
                nb_getval(link, LINK_NEW),
                nb_getval(rule, RULE_NEW)
                ; nb_linkval(rule, ''), nb_getval(rule, RULE)
        )
    ).

Upvotes: 1

Views: 159

Answers (2)

user741944
user741944

Reputation: 41

I’m assuming that by ‘flush’ you mean ‘forget’.

retractall/1 is what you desire.

Example :

?- assert(bottoms_on_fire(all_english_men)).

true.

?- assert(bottoms_on_fire(all_scottish_men)).

true.

?- bottoms_on_fire(all_english_men).

true.

?- retractall(bottoms_on_fire(_)).

true.

%note- use of the anonymous variable to unify with all such facts

?- bottoms_on_fire(all_english_men).

false.

Upvotes: 0

user123
user123

Reputation: 5407

Yeah, retract can help you to remove the facts from databse.

for p in self.prolog_question_identify.query("retract(linkage(_,_,_)),fail"):
    print

in linkage you can give which ever value you want to flush out.

Upvotes: 1

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