Using iex with BookManager app

book_manager_example.ex

### Stepping through class example on BookManager

# Import Ecto.Query first, or none of this works in iex:
import Ecto.Query

# A simple example
query = from BookManager.Book
BookManager.Repo.all(query)

# Creating aliases because BookManager is just to long to keep rewriting:
alias BookManager.Publisher
alias BookManager.Author
alias BookManager.Book
alias BookManager.BookAuthor
alias BookManager.Repo

# Looking at the example above again:
query = from BookManager.Book
Repo.all(query)
Repo.all(Book)
# ... gives me the same result

# Building up queries:
Book |> Book.alphabetical
Book |> Book.alphabetical |> Book.this_century
# Now execute the query on our repo:
Book |> Book.alphabetical |> Book.this_century |> Repo.all

# Get a specific book:  (! raises exception, no ! will return nil if missing)
dc = Repo.get_by!(Book, title: "The Divine Comedy")