Update attributes unless blank?

Question

I have an existing Project record, and I'm importing a CSV file to update the associated Project attributes. However, often the CSV will contain blank fields and I don't want to overright exisiting attributes if the related CSV field is blank.

Something like this:

project.update_attributes(:name => row.field('project_name') unless row.field('project_name').blank?,                                             
                          :owner => row.field('project_owner') unless row.field('project_owner').blank?,
                          :due_date => row.field('project_due_date') unless row.field('project_due_date').blank?)

Answer 1

project.update_attributes({:name => row.field('project_name'),                                                                         
                          :owner => row.field('project_owner'),
                          :due_date => row.field('project_due_date')}.reject{|k,v| v.blank?})

Answer 2

You can do this from the controller if needed:

def some_params
    params.permit(:foo, :bar).reject { |_, v| v.blank? }
end

In this case the attributes won't be saved if they are blank

Answer 3

This is an old question, but for the record, you can also set an attribute to nil (as opposed to blank) in order to exclude it from the updates list. I wouldn't call the following example best practice, but I think it can help clarify what's going on in the background: update_attributes will only attempt to update attributes that are provided in the hash, having a non-nil value.

params[:csv] = nil if params[:csv].blank? or (arbitrary other condition)
# now update like normal
if @project.update_attributes(project_params)
  ...
etc.