as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
construct a database table to maintain records of user activities.
user
create table user_activities (
  id integer primary key,
  user_id integer not null,
  activity_name varchar(20) not null,
  time_stamp timestamp default current_timestamp
);

alter table user_activities add foreign key (user_id) references user_info(id);
assistant