How to mock database operations in API calls using jest?

I've an API, It performs other operations and in the end it does database operations like creation or updation. I need to test that API using JEST and SUPERTEST, but when I test that API it makes changes in the database and I don't want that to happen, I need to mock that database operation using JEST. I want to test that API using JEST but should not affect the database. How can I able to achieve this? I couldn't find any good examples in the internet. Somebody help me to test it.