CREATE TABLE billing.payments (
    id serial NOT NULL,
    "number" int4 NOT NULL,
    payment_date DATE NOT NULL,
    bill int4 NOT NULL,
    user_id int4 NULL,
    accounted_date DATE NOT NULL DEFAULT now(),
    VALUE NUMERIC(14,2) NOT NULL,
    receipt int4 NULL,
    CONSTRAINT payments_pkey PRIMARY KEY (id),
    CONSTRAINT payments_un UNIQUE (NUMBER, payment_date, bill, VALUE),
    CONSTRAINT payments_bill_fkey FOREIGN KEY (bill) REFERENCES bills(id),
    CONSTRAINT payments_receipts_fk FOREIGN KEY (receipt) REFERENCES receipts(id) ON UPDATE CASCADE ON DELETE SET NULL,
    CONSTRAINT payments_user_id_fkey FOREIGN KEY (user_id) REFERENCES users(id)
);
CREATE INDEX payments_accounted_date_idx ON billing.payments USING btree (accounted_date);
CREATE INDEX payments_bill_idx ON billing.payments USING btree (bill);
CREATE INDEX payments_number_idx ON billing.payments USING btree (NUMBER);
CREATE INDEX payments_payment_date_idx ON billing.payments USING btree (payment_date);
CREATE INDEX payments_value_idx ON billing.payments USING btree (VALUE);