Can I use update_all on array?

Question

I have list of comments in one array. Can I use update_all on array ?

comments = Comments.find(:all,:conditions => ["test is not null"]) 

comments.update_all(:test => nil)

Answer 1

You cannot use update_all with arrays, only with scopes. find or all (in older version of Rails) return an array. Instead:

comments = Comments.scoped(:conditions => "test IS NOT NULL")
comments.update_all(:test => nil)

On modern versions of Ruby/ActiveRecord, you can write:

Comments.where.not(test: nil).update_all(test: nil)

Answer 2

update_all is a method provided by ActiveRecord, and what you have is an Array, you have two options either use ActiveRecord through Comments (will update database) or map the array, changing only the objets in memory and not modifying the database:

comments = Comments.update_all({:test => nil}, 'test IS NOT NULL')

or

comments = Comments.find(:all,:conditions => ["test is not null"])
comments.map! { |c| c.test = nil unless c.test}

EDIT: Error in the second example, is c.test not c