Express each of the following queries in an equivalentRelational Algebraquery andDatalogquery respectively against the relational schema defined above.

1) - For each customer, list his/her email and password.

- For each book purchased by a customer whose email is "anonymous@mail.com", list the book's title and the customer's purchase time.

- For each customer who has purchased at least one book, list the customer's email and the name of each device that belongs to this customer.

- For each book downloaded by any device belonging to a customer whose email is "anonymous@mail.com", list the title of the book, the download device's name and IP address, the download time, and the time of this book being purchased by the customer.

- List the title of each book that has NEVER been purchased by any customer.