login:- write('username: '), read(User), nl, write('password: '), read(Pass).

find(R):-findall(Row, rs('SELECT name FROM patient where name='James'', Row), R).

?- find(R).
 R = [row('James'), row('James'), row('James'), row('James')].

check:-findall(Row, rs('SELECT name FROM patient where name='James'', Row), R),
read(User), member(row(User), R);
write('wrong username!').

?- check.
|: Bla.
true ;
wrong username!
true.

?- check.
|: James.
true ;
wrong username!
true.