i have implemented the exercise on page 412,413. Everything is good. But there is a query. When I put the filter LIKE'%rock%', then in my filter column LIKE'%rock% changes to LIKE N'%rock%'. And similarly in my SQL pane (Name LIKE N'%rock%') was written.
I don't understand why this word 'N' is written all though you don't mentioned any thing about it in the book.