What is the difference between new and build?

What is the difference between

parent.children << child.new

and

parent.children.build(params[:child])

In the first one, the child is saved right away.
In the second, the child is not saved until the parent is saved

You may find this usefull:
http://blog.mrbrdo.net/2009/10/27/ruby-on-rails-new-vs-create-vs-build/

Sharagoz wrote:

In the first one, the child is saved right away.
In the second, the child is not saved until the parent is saved

You may find this usefull:
http://blog.mrbrdo.net/2009/10/27/ruby-on-rails-new-vs-create-vs-build/

Thanks Sharagoz. I got some idea about this.

Actually if the parent is not persisted, the shovel operator does not save data on db.