My instructions said on GUI I am just required to supply search/book(update) function. So from GUI side I don't provide the delete/create functionality. Then how the examiner to test my delete/create method on my database server?
he can test them the same way you can: by writing a small test application and running that. As the API is pretty standard between assignments, they can even have a large part of it predefined and just need to ask some launching stubs to interface with yours.