CREATE TABLE SKALAOCEN(
    ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1, INCREMENT BY 1),
    OCENA VARCHAR(3) NOT NULL,
    CONSTRAINT SKALAOCEN_PK PRIMARY KEY(ID)
);

CREATE TABLE PRZEDMIOT(
    ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1, INCREMENT BY 1),
    NAZWA VARCHAR(40) NOT NULL,
    CONSTRAINT PRZEDMIOT_PK PRIMARY KEY(ID)
);

CREATE TABLE STUDENT(
    ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1, INCREMENT BY 1),
    NRALBUMU INTEGER NOT NULL,
    IMIE VARCHAR(30) NOT NULL,
    NAZWISKO VARCHAR(30) NOT NULL,
    CONSTRAINT STUDENT_PK PRIMARY KEY(ID)
);

CREATE TABLE OCENA(
    ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1, INCREMENT BY 1),
    DZIEN DATE NOT NULL,
    STUDENT_ID INTEGER,
    PRZEDMIOT_ID INTEGER,
    SKALAOCEN_ID INTEGER,
    CONSTRAINT OCENA_PK PRIMARY KEY(ID),
    CONSTRAINT OCENA_FK1 FOREIGN KEY(STUDENT_ID) REFERENCES STUDENT(ID),
    CONSTRAINT OCENA_FK2 FOREIGN KEY(PRZEDMIOT_ID) REFERENCES PRZEDMIOT(ID),
    CONSTRAINT OCENA_FK3 FOREIGN KEY(SKALAOCEN_ID) REFERENCES SKALAOCEN(ID)
);