create table scheduled_operation(
  id serial primary key,
  start_date date not null,
  stop_date date not null,
  day integer not null check (day > 0 and day <= 31),
  frequency integer not null check (frequency > 0),
  label varchar(500) not null,
  value numeric(15,2) not null,
  account_id integer not null references account(id),
  category varchar(100)
);

create index scheduled_operation_account_id_idx on scheduled_operation(account_id);

alter table entry add column scheduled_operation_id integer references scheduled_operation(id);