数据库设计：课程、学生和教师表结构

CREATE TABLE course ( course_id INT PRIMARY KEY, course_name VARCHAR(50) NOT NULL, credit INT NOT NULL, teacher_id INT, FOREIGN KEY (teacher_id) REFERENCES teacher(teacher_id) );

CREATE TABLE student ( student_id INT PRIMARY KEY, student_name VARCHAR(50) NOT NULL, age INT NOT NULL, gender VARCHAR(10) NOT NULL );

CREATE TABLE teacher ( teacher_id INT PRIMARY KEY, teacher_name VARCHAR(50) NOT NULL, age INT NOT NULL, gender VARCHAR(10) NOT NULL );