-- 学生表
CREATE TABLE STUDENT
(
    ID INT PRIMARY KEY NOT NULL,
    STUDENT_NAME VARCHAR2(80),
    BIRTHDAY DATE,
    SEX VARCHAR2(2)
)
-- 课程表
CREATE TABLE COURSE
(
    ID INT PRIMARY KEY NOT NULL,
    COURSE_NAME VARCHAR2(80),
    TEACHER_ID INT
)
-- 教师表
CREATE TABLE TEACHER
(
    ID INT PRIMARY KEY NOT NULL,
    TEACHER_NAME VARCHAR2(80)
)
-- 成绩表
CREATE TABLE SCORE 
(
    ID INT PRIMARY KEY NOT NULL,
    STUDENT_ID INT,
    COURSE_ID INT,
    SCORE INT
)