create table answers
( id number generat
you may define foreign keys at the bottom, non-adjacent to column names, like below :
create table answers (
id number generated by default on null as identity primary key,
question_id number,
user_id number,
answer varchar(1000),
post_date date,
foreign key(question_id) references questions(id),
foreign key(user_id) references users(id)
);