尝试删除Heroku上的记录时，如何解决“ RuntimeError：无法修改冻结的哈希”？

Question

At my Rails console on Heroku, I am trying to do a simple array iteration and delete the record if a certain condition exists, and I am running into that error.

This is what I am doing:

irb(main):044:0> a.first
=> #<Activity id: 1, trackable_id: 3, trackable_type: "Node", owner_id: 5, owner_type: "User", key: "node.create", parameters: {}, recipient_id: nil, recipient_type: nil, created_at: "2014-07-30 11:22:15", updated_at: "2014-07-30 11:22:15", read_status: 0>
irb(main):045:0> a.first.trackable.nil?
=> false
irb(main):046:0> a.second.trackable.nil?
=> true
irb(main):061:0> a.each do |x|
irb(main):062:1* if x.trackable.nil?
irb(main):063:2> x.destroy
irb(main):064:2> x.save
irb(main):065:2> end
irb(main):066:1> end
RuntimeError: can't modify frozen Hash

Thoughts on how I can achieve this?

If I leave off the x.save it doesn't get rid of the record it seems.

Answer 1

You can't call .save on a destroyed record. Once you've called .destroy on the record, it's been removed from the database already; there's no use calling .save on it. If you're basing your determination of whether it's been destroyed by whether you still have access to it in Ruby's memory, you can call .destroyed? on a record to find out whether it's been destroyed or not.