In a Books table with columns BookID, ISBN, and Title, which of the following sets of columns can be considered a candidate key?

A candidate key in a database is a set of attributes that can be uniquely used to identify a database record without any extraneous data. Each table may have one or more candidate keys, but one candidate key is unique, and it is called the primary key.

In the context of a Books table with columns BookID, ISBN, and Title, the following sets of columns can be considered as candidate keys:

1. BookID: This is typically a unique identifier that is assigned to each book in the database. Therefore, it can be used as a candidate key.

2. ISBN: The International Standard Book Number (ISBN) is a unique commercial book identifier barcode. Each ISBN is unique to a specific book, so this can also be used as a candidate key.

The Title of the book cannot be considered as a candidate key because different books can have the same title.

So, the sets of columns that can be considered as candidate keys are {BookID} and {ISBN}.