Solution to Databases - Keys
bookname-author-language
A Tale of Two Cities, Charles Dickens, English
Oliver Twist, Charles Dickens, English
Godaan, Premchand, Hindi
Chandrakanta, Devaki Nandan Khatri, Hindi
Hamlet, William Shakespeare, English
The Merchant of Venice, William Shakespeare, English
A primary key is a special relational database table column (or combination of columns) designated to uniquely identify each table record.
Answer
bookname - these are unique between books. However, primary keys are normally numbers.