Rails destroy_all undo

Question

I've accidentally erased all the records from one my model.

Model.destroy_all

For the output I've received a large list for all the records that have been destroyed.

=> [#<Model id: 1, some_attribute: "Hello World">, #<Model id: 2, some_attribute: " Hello World 2">, etc etc etc]

But, I've got it a text. Can I do anything, using IRB, to return the records back ?

This is very, VERY urgent! Any help is appreciated.

Thank you so much

score 2 · Answer 1 · answered Sep 27 '13 at 11:44

here's a quick test I made on my model:

1. pry(main)> output = JobUser.first(10).to_s

=> "[#<JobUser id: 10001, instagram_user_id: 297705889, job_id: 2, invited: true, created_at: \"2013-09-23 21:53:37\", updated_at: \"2013-09-23 21:53:37\">, #<JobUser id: 10002, instagram_user_id: 36823356, job_id: 2, invited: true, created_at: \"2013-09-23 21:53:37\", updated_at: \"2013-09-23 21:53:37\">, #<JobUser id: 10003, instagram_user_id: 509682835, job_id: 2, invited: true, created_at: \"2013-09-23 21:53:37\", updated_at: \"2013-09-23 21:53:37\"> ....

2.

parsed = output.gsub('#<', '').gsub('>', '').gsub(/^\[/, '').gsub(/\]$/, '').split('JobUser').map(&:strip)

=>

     "id: 10001, instagram_user_id: 297705889, job_id: 2, invited: true, created_at: \"2013-09-23 21:53:37\", updated_at: \"2013-09-23 21:53:37\",",
     "id: 10002, instagram_user_id: 36823356, job_id: 2, invited: true, created_at: \"2013-09-23 21:53:37\", updated_at: \"2013-09-23 21:53:37\",",
     "id: 10003, instagram_user_id: 509682835, job_id: 2, invited: true, created_at: \"2013-09-23 21:53:37\", updated_at: \"2013-09-23 21:53:37\"...

3. parsed.shift because the first element in array will be a blank string

4. records = parsed.map { |serialized_record| JobUser.new(eval "{ #{serialized_record} }") }

then you should probably run something like records.each { |record| record.save }

Please note that you should replace JobUser with your model name. The point is you'll have to parse the string and insert it back into database

good luck!

Thank you very much for your response! I'm going to try it right away — Dmitri, Sep 27 '13 at 11:52
Can you suggest what should I do if I have a BigDecimal column entry ? Because of it I have an error at step 4: "syntax error, unexpected tLABEL" Do I need to parse it somehow ? Thank you — Dmitri, Sep 27 '13 at 12:02

Arne · Accepted Answer · 2013-09-27T13:50:23.643

2

The following script should do the trick:

require 'bigdecimal'

str = "#<Model id: 1, some_attribute: #<BigDecimal:4ba0730,'0.0',9(18)>, another_attribute: \"Hello World\">, #<Model id: 2, some_attribute: \" Hello World 2\">"

str.scan(/#?<(\w+) (.+?)>(?=, #|$)/) do |m|
    model = Object.const_get(m[0])
    m[1].gsub!(/#<BigDecimal:.+?('.+?').+?>/, "BigDecimal.new(\\1)")
    eval("model.create(#{m[1]})")
end

This also handles instances of BigDecimal. In case you need to handle other special types you can just add another call to gsub!.

edited Sep 27 '13 at 13:50

answered Sep 27 '13 at 11:52

Arne

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Thank you for your answer! How can I enhance my second capture group if I have a "# – Dmitri Sep 27 '13 at 12:09
Careful with double quotes, I had a problem when including dates in mine, datetime's had double quotes in them, but by doing `str = 'blah'` it seemed to work – Tom Prats Apr 20 '14 at 07:07

Rails destroy_all undo

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