What creates! mean in rails?

Question

What does this do in Rails?

create! do |user| #initialise user end 

I decided that it creates user objects and stores it in the database. How does this differ from the simple expression user.new(...) and user.save() ?

Answer 1

In a nutshell:

• create! throws an exception, and create returns an object (an unsaved object if it fails validation).
• save! causes an error, and save returns true / false .
• save does not accept attributes, create .

new does not save. new similar to the ActiveRecord context build . create saves the database and returns true or false depending on the model validation. create! saves the database, but throws an exception if there are errors in the verification of the model (or any other error).

Answer 2

When failed to create a record, create! throws an exception, new and then save (or just create without an exclamation point) exit silently.

Answer 3

create accepts attributes, so using a block here is somewhat unusual. The code you mentioned performs initialization in the block that is passed to create! It basically coincides with new , followed by initialization, and then a save!

There are many options for saving, saving !, creating, terminating !, updating, updating !, etc. there are also variations in terms of validations and backlinks

See API for more details: (this is discussed in the first link)

http://api.rubyonrails.org/classes/ActiveRecord/Base.html

http://apidock.com/rails/ActiveRecord/Base

http://m.onkey.org/active-record-query-interface