CREATE TABLE USERS
    (USERID NUMBER(9) PRIMARY KEY,
    FIRSTNAME VARCHAR(20) NOT NULL,
    LASTNAME VARCHAR(20) NOT NULL,
    EMAIL VARCHAR(30) NOT NULL,
    PASSWORD VARCHAR(12) NOT NULL,
    USERTYPE CHAR(4) NOT NULL);

CREATE TABLE ASSIGNMENTS
    (ASSIGNMENTID CHAR(8) PRIMARY KEY,
    MAXSCORE NUMBER(4) NOT NULL,
    ASSIGNTYPE CHAR(4) NOT NULL);

CREATE TABLE QUESTIONS
    (QUESTIONID CHAR(8) PRIMARY KEY,
    ASSIGNMENTID CHAR(8),
    QUESTION CHAR(100) NOT NULL,
    CHOICE1 VARCHAR(1),
    CHOICE2 VARCHAR(1),
    CHOICE3 VARCHAR(1),
    CHOICE4 VARCHAR(1),
    ANSWER CHAR(4),
    TIMER NUMBER(4),
FOREIGN KEY (ASSIGNMENTID) REFERENCES ASSIGNMENTS);

CREATE TABLE SCORES
    (ASSIGNMENTID CHAR(8),
    STUDENTID NUMBER(9),
    SCORE NUMBER(4),
PRIMARY KEY (ASSIGNMENTID, STUDENTID),
FOREIGN KEY (ASSIGNMENTID) REFERENCES ASSIGNMENTS,
FOREIGN KEY (STUDENTID) REFERENCES USERS);