Answer:
Fields are the components that provide structure for a table. Fields in a table store the same category of data in the same data type. For example, if you have a NAME field in a table of customers, the entries for this field are all customer names and are stored as text.
A primary key is a field or set of fields with values that are unique throughout a table. Values of the key can be used to refer to entire records, because each record has a different value for the key. Each table can only have one
primary key.
The primary key of this table is the ISBN, which uniquely identifies a book. The title column relates to the book; this is the title of the book. Each row of this table is about one book.