DAIS - PL-SQL - create

/**
@Author: Sajmon
*/

CREATE TABLE Reservation
    (
     coachNumber INTEGER  NOT NULL ,
     seatNumber INTEGER  NOT NULL ,
     reservationDate DATE  NOT NULL ,
     paidDate DATE ,
     canceledDate DATE ,
     idTrainRide INTEGER  NOT NULL ,
     idUser INTEGER
    )
;



ALTER TABLE Reservation
    ADD CONSTRAINT Reservation_PK PRIMARY KEY ( coachNumber, seatNumber, idTrainRide ) ;


CREATE TABLE Staff
    (
     idStaff INTEGER  NOT NULL ,
     fname VARCHAR2 (30)  NOT NULL ,
     lname VARCHAR2 (30)  NOT NULL ,
     POSITION CHAR (1)  NOT NULL ,
     jobStart DATE  NOT NULL ,
     jobEnd DATE ,
     salary INTEGER  NOT NULL
    )
;



ALTER TABLE Staff
    ADD CONSTRAINT Staff_PK PRIMARY KEY ( idStaff ) ;


CREATE TABLE Station
    (
     idStation INTEGER  NOT NULL ,
     name VARCHAR2 (60)  NOT NULL
    )
;



ALTER TABLE Station
    ADD CONSTRAINT Station_PK PRIMARY KEY ( idStation ) ;


CREATE TABLE Train
    (
     idTrain INTEGER  NOT NULL ,
     name VARCHAR2 (20)  NOT NULL ,
     coachCount INTEGER  NOT NULL ,
     price FLOAT  NOT NULL ,
     startTime DATE  NOT NULL ,
     endTime DATE  NOT NULL ,
     idStation INTEGER ,
     idStation1 INTEGER
    )
;



ALTER TABLE Train
    ADD CONSTRAINT Train_PK PRIMARY KEY ( idTrain ) ;


CREATE TABLE TrainCrew
    (
     idStaff INTEGER  NOT NULL ,
     idTrainRide INTEGER  NOT NULL
    )
;



ALTER TABLE TrainCrew
    ADD CONSTRAINT PK_TrainCrew PRIMARY KEY ( idStaff, idTrainRide ) ;


CREATE TABLE TrainRide
    (
     idTrainRide INTEGER  NOT NULL ,
     rideDate DATE  NOT NULL ,
     idTrain INTEGER
    )
;



ALTER TABLE TrainRide
    ADD CONSTRAINT TrainRide_PK PRIMARY KEY ( idTrainRide ) ;


CREATE TABLE "User"
    (
     idUser INTEGER  NOT NULL ,
     email VARCHAR2 (30)  NOT NULL ,
     fname VARCHAR2 (40) ,
     lname VARCHAR2 (40) ,
     password VARCHAR2 (12)  NOT NULL
    )
;



ALTER TABLE "User"
    ADD CONSTRAINT User_PK PRIMARY KEY ( idUser ) ;



ALTER TABLE TrainCrew
    ADD CONSTRAINT Relation_1 FOREIGN KEY
    (
     idStaff
    )
    REFERENCES Staff
    (
     idStaff
    )
;


ALTER TABLE TrainCrew
    ADD CONSTRAINT Relation_3 FOREIGN KEY
    (
     idTrainRide
    )
    REFERENCES TrainRide
    (
     idTrainRide
    )
;


ALTER TABLE TrainRide
    ADD CONSTRAINT Relation_4 FOREIGN KEY
    (
     idTrain
    )
    REFERENCES Train
    (
     idTrain
    )
    ON DELETE SET NULL
;


ALTER TABLE Reservation
    ADD CONSTRAINT Relation_5 FOREIGN KEY
    (
     idTrainRide
    )
    REFERENCES TrainRide
    (
     idTrainRide
    )
;


ALTER TABLE Reservation
    ADD CONSTRAINT Relation_6 FOREIGN KEY
    (
     idUser
    )
    REFERENCES "User"
    (
     idUser
    )
    ON DELETE SET NULL
;


ALTER TABLE Train
    ADD CONSTRAINT Relation_7 FOREIGN KEY
    (
     idStation
    )
    REFERENCES Station
    (
     idStation
    )
    ON DELETE SET NULL
;


ALTER TABLE Train
    ADD CONSTRAINT Relation_8 FOREIGN KEY
    (
     idStation1
    )
    REFERENCES Station
    (
     idStation
    )
    ON DELETE SET NULL
;