CREATE TABLE charges (
  id                 SERIAL,
  metering_point_id  VARCHAR(18) NOT NULL REFERENCES metering_points(metering_point_id),
  charge_type        VARCHAR(20) NOT NULL,
  name               VARCHAR(200) NOT NULL,
  description        VARCHAR(500),
  owner              VARCHAR(100) NOT NULL,
  valid_from_date    DATE NOT NULL,
  valid_to_date      DATE,
  period_type        VARCHAR(50),
  price              NUMERIC(12,6),
  quantity           INTEGER,
  position           INTEGER NOT NULL DEFAULT 0,
  fetched_at         TIMESTAMPTZ NOT NULL DEFAULT now(),
  UNIQUE (metering_point_id, charge_type, name, owner, valid_from_date, position)
);