Prolog getting dynamic fact values -

while learning prolog, writing text-based game, of it:

newhealth health - damage, retract(stat(target, health, health)), assert(stat(target, health, newhealth)), 

i got error static procedures simple search fixed it, when running game dynamic stat/3. after however, error further in file declare health variable:

stat(target, health, health), 

i narrowed down problem (prolog console):

| ?- assert(test(a)). yes | ?- listing test(a). yes | ?- dynamic test/1 yes | ?- listing yes 

after being declared dynamic, isn't in static database anymore. google search couldn't find case has same problem mine. need query , retract/assert single database.

dynamic/1 directive. place near top of file, syntax

:- dynamic stat/3.