variables - Binding symbols and querying symbol values in Prolog -

i have difficulty doing basic things in swi prolog. starters, how have function binds symbol value? here's tried, don't know if it's correct:

bind(name) :- assert(name = 'a').

now if run bind(test). in interpreter symbol test bound value 'a'. way it? if is, how query value of symbol?

are asking such basic thing unification in prolog?

if have predicate

bind('a').

defined, in other predicate, after calling

.... ,    %// #1 bind(x),  %// #2 ....

x hold 'a' value below point #2, until backtracking occurs (if any) above point #2.

but there's no need separate bind predicate that. unification signified =/2 built-in operator, , same effect achieved with

.... ,    %// #1 x = 'a',  %// #2 ....

if try in swi prolog console,

1 ?- x = 'a'. x = 'a'.

you can access later

2 ?- z = $x. z = 'a'.

but if want more tangible, should assert database, under functor name of choice, you're advised in capellic's answer.

Three