Call a class from another class - Ruby on Rails

Question

I searched around the SOF and couldn't find a simple answer for my simple question.

I have two classes, Author and Book.

class Author < ActiveRecord::Base def greet puts "Hello, I'm #{name}." end def describe puts "That Author's name is #{name}. puts "This author wrote this book #{book}." #<--- I want to write this or combine it with the line above end end

In class book, I don't have anything just

class Book < ActiveRecord::Base end

How can I puts the following: That Author's name is ... and This author wrote this ... when I enter Author.first.describe in the Rails console?

firstly few syntax error in the code, also what are you trying to achieve here.. im not getting. — Hardik Gondaliya
– Hardik Gondaliya, Commented Jan 31, 2017 at 1:15
as stated above, its not quite clear what your goal is, do you have any relations defined that connect Author and Book? What is your expected output from the #{book} segment in your string? What have you attempted so far? More information and clarity would go a long way to helping us provide an answer for you — John Hayes-Reed
– John Hayes-Reed, Commented Jan 31, 2017 at 1:17
@JohnHayes-Reed Each author has a 1 book and it's assigned to him in his table with a book_id which matches the book_id in the books table. — Mustafa
– Mustafa, Commented Jan 31, 2017 at 1:55
I have written an answer based on the information you just commented, hope it can help you or get you on your way. — John Hayes-Reed
– John Hayes-Reed, Commented Jan 31, 2017 at 2:14

John Hayes-Reed · Accepted Answer · 2017-01-31 02:13:45Z

based on the information you gave me in the comment your relations would look something like this:

class Author < ActiveRecord::Base belongs_to :book end class Book < ActiveRecord::Base has_one :author end

The describe method in your Author class could look something like

def describe "That Author's name is #{name}. This author wrote this book #{book.title}." end

This is based on you stating you have the book_id in your authors table, and I am also assuming you have a title or name field in your books table.

However, it feels more natural to have the Author owning the book, and the book belonging to the Author, so might I suggest changing your data structure a bit to remove the book_id from authors table, and instead place an author_id in book table, and then your models relations would look like this:

class Author < ActiveRecord::Base has_one :book end class Book < ActiveRecord::Base belongs_to :author end

Thank you, I think I messed up the relationships, and it's working now!

Carlos Chiw · Accepted Answer · 2017-01-31 01:39:14Z

class Author < ActiveRecord::Base has_many :books class Book < ActiveRecord::Base belongs_to :author

and in the migration author:references

 class CreateServices < ActiveRecord::Migration[5.0] def change create_table :services do |t| t.string :title t.text :description t.text :require t.integer :price t.references :user, foreign_key: true t.timestamps end end end

this is a project i'm working on, i'm using user but in your case is author.

Thank you, I actually have the tables set up. I just need to output the author's name and the books when I enter for example: Author.first.describe in the console
Thank you, I think I messed up the relationships, and it's working now!

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