DROP TABLE IF EXISTS students;
DROP TABLE IF EXISTS courses;
DROP TABLE IF EXISTS enrollments;

CREATE TABLE students (
    student_id TEXT PRIMARY KEY,
    first_name TEXT,
    last_name TEXT
);

CREATE TABLE courses (
    department_code TEXT,
    course_number INTEGER,
    course_title TEXT,
    PRIMARY KEY (department_code, course_number)
);

CREATE TABLE enrollments (
    student_id TEXT,
    department_code TEXT,
    course_number INTEGER,
    section_number INTEGER,
    PRIMARY KEY (student_id, department_code, course_number),
    FOREIGN KEY (student_id) 
        REFERENCES students (student_id),
    FOREIGN KEY (department_code, course_number) 
        REFERENCES courses (department_code, course_number)
);

.mode csv
.import students.csv students
.import courses.csv courses
.import enrollments.csv enrollments