PRAGMA foreign_keys = ON;
CREATE TABLE students (
    id INTEGER PRIMARY KEY,
    name TEXT NOT NULL,
    city TEXT,
    score INTEGER NOT NULL CHECK (score BETWEEN 0 AND 100),
    cohort TEXT NOT NULL
);
CREATE TABLE courses (id INTEGER PRIMARY KEY, title TEXT NOT NULL UNIQUE);
CREATE TABLE enrollments (
    student_id INTEGER NOT NULL REFERENCES students(id),
    course_id INTEGER NOT NULL REFERENCES courses(id),
    PRIMARY KEY (student_id, course_id)
);
INSERT INTO students VALUES
    (1, 'Asha', 'Jaipur', 82, 'Java'),
    (2, 'Aman', 'Ajmer', 66, 'Java'),
    (3, 'Jaya', 'Jaipur', 94, 'SQL'),
    (4, 'Kiran', NULL, 48, 'SQL'),
    (5, 'Neha', 'Kota', 82, 'SQL'),
    (6, 'Kabir', 'Jaipur', 40, 'Java');
INSERT INTO courses VALUES (10, 'Java'), (20, 'SQL'), (30, 'Python');
INSERT INTO enrollments VALUES (1, 10), (1, 20), (2, 10), (3, 20), (5, 20);