Cruise tables in postgresql

BEGIN;
CREATE SCHEMA IF NOT EXISTS chapter4;

DROP TABLE IF EXISTS chapter4.RESERVATION_CUSTOMER;
DROP TABLE IF EXISTS chapter4.CUSTOMER;
DROP TABLE IF EXISTS chapter4.CREDIT_CARD;
DROP TABLE IF EXISTS chapter4.RESERVATION;
DROP TABLE IF EXISTS chapter4.CRUISE;
DROP TABLE IF EXISTS chapter4.ID_GENERATION;


CREATE TABLE chapter4.CREDIT_CARD
   (
      ID SERIAL NOT NULL PRIMARY KEY,
      EXP_DATE DATE NOT NULL,
      NUMBER VARCHAR(25) NOT NULL,
      ORGANIZATION VARCHAR(55) NOT NULL
   );

CREATE TABLE chapter4.CUSTOMER
   (
      ID SERIAL NOT NULL PRIMARY KEY,
      FIRSTNAME VARCHAR(50) NOT NULL,
      NAME VARCHAR(50) NOT NULL,
      CREDIT_CARD_ID BIGINT REFERENCES chapter4.CREDIT_CARD(ID)
   );

CREATE TABLE chapter4.CRUISE
   (
      ID SERIAL NOT NULL PRIMARY KEY,
      NAME VARCHAR(25) NOT NULL,
      DESCRIPTION VARCHAR(255)
   );

CREATE TABLE chapter4.RESERVATION
   (
      ID SERIAL NOT NULL PRIMARY KEY,
      AMOUNT_PAID float8 NOT NULL,
      DATE_RESERVED DATE NOT NULL,
      CRUISE_ID BIGINT REFERENCES chapter4.CRUISE(ID)
   );

CREATE TABLE chapter4.RESERVATION_CUSTOMER
   (
      RESERVATION_ID SERIAL NOT NULL REFERENCES chapter4.RESERVATION(ID),
      CUSTOMER_ID BIGINT NOT NULL REFERENCES chapter4.CUSTOMER(ID),
      PRIMARY KEY (RESERVATION_ID, CUSTOMER_ID)
   );
COMMIT;