how to understand callback and validate_associated

rubyonrails-talk
1

1 after_update callback is wrapped in transaction means:no matter exception occurs during saving an existing record, or in the after_update method body,both the existing record and record manipulation in the after_update body are all rollbacked?

2 class Book < ActiveRecord::Base     has_many :pages     validates_associated :pages     validates_presence_of :name    end

validate_associated means: when i invoke book.save to save book and it's associations,no matter invalidation occurs during saving book self or saving any association,both book and all the associations don't be saved?

I don't understand these from document.can you help me to make it sure? Thanks!

2

anyone help me?

3

hi   who know about it? thanks!

4

hi who know about it? thanks!

Maybe you could rephrase your question - I for one couldn't understand what you were asking

Fred

5

thank! I copy the after_update() doc as following:

6

I have described the problem clearly.Can you help me?

7

Correct. The entirety of the save process (validations, before_save, after_save etc.) is wrapped in a single transaction.

Fred

8

Thanks,fred.