Permits That Vanish With the Student

Create parking_permits: id INTEGER PRIMARY KEY; student_id INTEGER NOT NULL that REFERENCES students(id) with ON DELETE CASCADE; plate TEXT NOT NULL UNIQUE; and expires_on TEXT (optional). The cascade means that when a student row is deleted, their permits are deleted with it instead of blocking the delete: the checker gives student 1 a permit and then deletes student 1, which must succeed. Two permits for the same plate must be refused.

Expected result:

Table parking_permits
✓ id INTEGER PRIMARY KEY
✓ student_id INTEGER NOT NULL
✓ plate TEXT NOT NULL
✓ expires_on TEXT
✓ student_id REFERENCES students(id)
✓ UNIQUE (plate)
✓ Deleting student 1 after giving them a permit: accepted
✓ Two permits for plate ABCD 123: rejected (UNIQUE)
✓ A permit for student 99: rejected (FOREIGN KEY)
✓ A permit with no expiry date: accepted

Hints3 available

Topics:

CREATE TABLE

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