Hi Mani,

So this seems more a general C# question, so my answer will be with that in mind, if that is not correct then let me know.

So, you author could be as follows:

 public class Author
 {
     public int Id{get;set;}
     public string Name{get;set}
     ...
 }

and your books could be:

public class Book{
    public int Id{get;set;}
    public int AuthorId{get;set;}
}

The Book.AuthorId would be the same Id the Author has, so you could then use this Id to get the Authors details such as name etc.

If i were to add this to an Umbraco site, or a general site I would probably use a code first approach, this allows you to have strongly typed classes (objects) within classes, so you when you get your Book, youll get your Author back as well. See here for some more details https://learn.microsoft.com/en-us/ef/ef6/modeling/code-first/workflows/new-database

Lewis