user = User.query.get(5)
db.session.delete(user)
db.session.commit()
**DELETE** plusieurs lignes selon un critère :
users = User.query.filter_by(active = True).all()
for user in users:
db.session.delete(user)
db.session.commit()
**DELETE** toutes les lignes :
User.query.delete()
db.session.commit()