create table work_memo (
    id            bigserial primary key,
    org_id        bigint       not null references organization (id) on delete cascade,
    contact_name  varchar(100) not null,
    body          text         not null,
    created_at    timestamptz  not null default now()
);

create index ix_work_memo_org_created on work_memo (org_id, created_at desc);