What's the advantage of using build and <<?

Rails
1

Rails give us two ways to create a asociation object:
@article = Article.new(params[:article])
@article.comments << Comment.new(params[:comment])
@article.save!
or

@article = Article.new(params[:article])
@comment = @article.comments.build(params[:comment])
@article.save!
@comment.save!

what’s the advantage of using build and << ??

2

<< should save @article when you add a new comment.

Ryan B.
Freelancer

3

<< adds records to a association-collection (no matter what kind of
association). it returns itself (the collection) so method calls may
be chained.

btw: in this example @article doesn’t have to be saved when a new
comment is added (comment has article_id as foreign key). :wink:

4

just saw that this could be misunderstood:
article has to be saved to be able to make a association, but it
doesn’t have to be saved after adding a new comment.

5

MaD wrote:

<< adds records to a association-collection (no matter what kind of
association). it returns itself (the collection) so method calls may
be chained.

btw: in this example @article doesn’t have to be saved when a new
comment is added (comment has article_id as foreign key). :wink:

what’s does that -method calls may be chained-? can you make me a
concrete example?

in this example @article doesn’t have to be saved when a new

comment is added (comment has article_id as foreign key)
=
@article = Article.new(params[:article])
don’t we have to save it for store a Article instance?