select
    s.id, s.name, st.name, p.firstname || ' ' || p.lastname,
    f.name, f.store_date, bdt.name, bd.comment
from
    system s, systemstatus st, role w, person p, file f,
    documenttype bdt, document bd
where
    w.system_id = s.id and
    p.id = w.person_id and
    st.id = s.status_id and
    bd.system_id = s.id and
    bd.file_id = f.id and
    bd.type_id = bdt.id and
    bd.role_id = w.id;

select
    s.id, s.name, st.name, p.firstname || ' ' || p.lastname, f.name,
    f.store_date, bdt.name, bd.comment
from system as s
    left outer join systemstatus as st on st.id= s.status_id
    left outer join role as w on w.system_id = s.id
    left outer join person as p on p.id = w.person_id
    left outer join document as bd on bd.system_id = s.id and bd.role_id = w.id
    left outer join documenttype as bdt on bdt.id = bd.type_id
    left outer join file as f on f.id = bd.file_id

select *
from system s
left join role w on w.system_id = s.id
left join person p on p.id = w.person_id