public class BaseModel
{
    public BaseModel()
    {
        IsActive = true;
    }

    public int Id { get; set; }

    public bool IsActive { get; set; }

    public DateTime CreatedDate { get; set; }

    public string CreatedUser { get; set; }

    public DateTime UpdatedDate { get; set; }

    public string UpdatedUser { get; set; }
}

public class Category : BaseModel
{
    public string Name { get; set; }
}

public class Book : BaseModel
{
    public string Title { get; set; }

    public int CategoryId { get; set; }

    public virtual Category Category { get; set; }

    public virtual ICollection<Person> Authors { get; set; }
}

public class Person : BaseModel
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public virtual ICollection<Book> Books { get; set; }
}