Preventing model from saving

rubyonrails-talk
1

I have a scenario where I have to prevent objects from saving to the database if they have a certain value and I want to come up with the optimal way to achieve that.

In my scenario, upon form submit, I will send 20 rows to the update action in the controller. However, I want to discard the 95% of them that have a particular attribute value to save database rows.

I'm not sure I want to traverse the hashes: params[:parentobject][:childobject][:grandchildobject][10][attributes][.... within the update action and loop through the objects and delete them if they have a particular value.

doing a before_save method within the model being destroyed: self.destroy if self.status = "something" doesn't seem to be a good option.

Any other ideas?

2

You could use a validation. That would be the normal method. Then you can just call save and only the valid ones will actually be saved.

Colin

3

Colin Law wrote in post #990706:

4

accepts_nested_attributes_for takes :reject_if => :method_name (or Proc.new{|obj| obj.some_value == i})

Garrett Lancaster

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5

I am not sure you made it entirely clear that you were using accepts_nested_attributes_for, but perhaps in retrospect it was fairly obvious. In which case you are right and Garrett's suggestions may be the way to go.

Colin

6

Thank you all. The winning line of code is, for future readers' benefit:

accepts_nested_attributes_for :item_statuses, :reject_if => Proc.new{|obj| obj['status'] == 'i'}