 comment on column users.birth_date_mask is 'Mask Flag to know wich part of the date is effectively known: 32 for year, 16 for month and 8 for day';
 comment on column users.birth_date is 'Birth/Creation date composed';
 comment on column users.gender is 'For physical users give the gender: M or F';
+comment on column users.last_seen is 'Last time the user has logged in.';
 
 create sequence people_languages_id_seq;
 

        id integer not null default nextval('users_id_seq'),
        db_user_type smallint default 1 not null,
        people_id integer,
        constraint pk_users primary key (id),
        constraint unq_users unique (is_physical, gender, formated_name_indexed, birth_date),
        constraint fk_user_people_id foreign key (people_id) references people(id) on delete set NULL

        user_name varchar,
        password varchar,
        login_system varchar,
        constraint pk_users_login_infos primary key (id),
        constraint unq_users_login_infos unique (user_ref, login_type),
        constraint fk_users_login_infos_users foreign key (user_ref) references users(id) on delete cascade
