CODEWITHSUNDEEP
ruby-on-railsactiverecord
KilgoreTrout
KilgoreTrout

Reputation: 73

Rails 5.0.2 - ID in relation belongs_to/has_many

I am new on RAILS, so don't hit me. I consider such problem:

- author
    has_many :books
- book
    belongs_to :author

In console I create a new author, per example:

ar = Author.new(fname: "Frank", lname: "Herbert")

ID of this record is not set before save.

Then I create some books from object ar:

ar.books.new(title: "Dune"), ar.books.new(title: "The Green Brain")

No errors. But when I list books: 

ar.books.all

got an empty list. I figured out that first I have to save ar, and then I can add books.

Is there a way to save ar with books, no need saving ar without books before?

Upvotes: 2

Views: 99

Answers (2)

puneet18
puneet18

Reputation: 4427

Follow below code: First create Author and then create books with author as foreign key.

ar = Author.new(fname: "Frank", lname: "Herbert")
ar.save

ar.books.create(title: "Dune")
ar.books.create(title: "The Green Brain")

OR

ar = Author.new(fname: "Frank", lname: "Herbert")
ar.books.build(title: "Dune")
ar.books.build(title: "The Green Brain")
ar.save

Upvotes: 1

nautgrad
nautgrad

Reputation: 414

Sure you can!

You need to call ar.books to look up for books that you have added. When you call ar.books.all ActiveRecord tries to find something in database (obviously it returns empty array). So just:

author = Author.new(fname: "Frank", lname: "Herbert")
author.books.build(title: "Dune")
author.save

It will save author & books as you expect. By the way use build method instead of new. In this way you show that you are going to create record soon.

Upvotes: 1

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