How to save data directly from the migration file in ruby on rails - mysql

Question

In my ROR project, I came across an issue. Previous developer of the project has save an array of data into a single column for a particular field. But now I have to get those data and save it to another separate table with the current table id. Following is my code for get the details from the db:
#ar = AResponse.select("id, selected_barriers");
#ar.each do |p|
p.selected_barriers.each do |barrier|
end
end
What I wanted is I have to save the p.id and barrier to a new table and I have to do it in a migration file. So when the migration runs, it will get all the existing details from AResponse and save it to the new one. Can I do it only with migration file? If so how can I do it?
This is my full code
I tried but its not working: Following is my code
class AnalysisBarriers < ActiveRecord::Migration
def self.up
end
def change
create_table :analysis_barriers do |t|
t.integer :analysis_response_id, :null => false
t.string :barrier
end
#analysis_response = AnalysisResponse.select("id, selected_barriers");
#analysis_response.each do |p|
p.selected_barriers.each do |barrier|
AnalysisBarriers.create(:analysis_response_id => p.id, :barrier => barrier)
end
end
end
def self.down
drop_table :analysis_barriers
end
end
Thanks

Answer 1

Yes you can do data changes after migrations. Whatever data changes you want to do, you can do in change function or up function. Take the following example
class Event < ActiveRecord::Migration
def change
create_table events do |t|
t.datetime :starts_at
t.datetime :ends_at
t.timestamps
end
Event.create(:starts_at => Time.now, :ends_at => Time.now+1)
end
end
Above statement will add data to your table just after its creation.