For single instance migration we could do like this,what to be done if i
want to migrate single instance with the relation?
On Sunday, October 27, 2013 9:57:57 AM UTC+5:30, Kashif Umair Liaqat wrote:
>
> 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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