You might need to write a migration or rake task for this purpose.
Migration may look like this.
class MigrateData < ActiveRecord::Migration
def change
get_all_models.each do |model|
model.where('').find_each do |model_instance|
model_instance.update_attributes id: UUIDTools::UUID.random_create.to_s
end
end
end
def get_all_models
Module.constants.select do |constant_name|
constant = eval constant_name
if not constant.nil? and constant.is_a? Class and constant.superclass ==
ActiveRecord::Base
constant
end
end
endend
This migration will iterate over all the models in your app and generate
UUID for each single instance.
On Friday, October 25, 2013 6:17:55 PM UTC+5, kingston.s wrote:
>
> Hi all,
>
> I am using rails 3.1 and ruby 1.9.3,Now i want to use uuid concept in
> rails 3 for existing data
>
> so i did like :-
>
> create_table :posts, :id => false do |t|
> t.string :uuid, :limit => 36, :primary => true
> end
>
> ActiveRecord::Base.class_eval do
>
> # old rails versions
> set_primary_key 'uuid'
>
> before_create :generate_uuid
> def generate_uuid
> self.id = UUIDTools::UUID.random_create.to_s
> end
> end
>
>
> This is working for new data,now i want to migrate existing data with
> relation.for uuid they are using datatype as string,in postgresql the
> data type used for primary_key and foreign key is integer ,so if i am
> trying to change foreign key integer to string it is throwing error.
>
> Could you please tell me some example,how to do this.
>
> kingston.s
>
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