def get_all_groups(): return bson_to_json(groups.find())
def get_group_by_name(name): return bson_to_json(groups.find_one({'name': name}))
def get_group_children(child_name): return bson_to_json(groups.find({'parent': child_name}))
def get_all_users(): return bson_to_json(users.find())
def get_user_by_name(username): return bson_to_json(users.find_one({'username': username}))
def get_user_by_id(user_id): if not isinstance(user_id, ObjectId): user_id = ObjectId(user_id) return bson_to_json(users.find_one({'_id': user_id}))
def get_all_exercises(): return bson_to_json(get_all_exercises_from_db())