將序列化數組轉換爲PSQL數組，錯誤

Question

因此，我正在嘗試執行一個需要現有列（它是序列化數組（文本））並將其轉換爲psql數組的遷移。我嘗試了很多東西，但不斷收到錯誤。

這是我的移民是什麼樣子：

class RenameColumn < ActiveRecord::Migration 
    def up 
     rename_column :table_things, :column, :old_column 

     add_column :table_things, :column, :text, :array => true, null: false, :default => [] 

     TableThing.class_eval do 
     serialize :old_column, Array 
     end 

     TableThing.reset_column_information 

     TableThing.find_each{|tt| 
     tt.column = tt.old_column 
     tt.save! 
     } 
    TableThing.reset_column_information 
     remove_column :table_things, :old_column 
    end 

，這是堆棧跟蹤：

rake aborted! 
An error has occurred, this and all later migrations canceled: ActiveRecord::RecordNotSaved/Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/persistence.rb:125:in `save!' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/validations.rb:57:in `save!' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/attribute_methods/dirty.rb:41:in `save!' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/transactions.rb:275:in `block in save!' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/transactions.rb:330:in `block in with_transaction_returning_status' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/transactions.rb:209:in `transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/transactions.rb:327:in `with_transaction_returning_status' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/transactions.rb:275:in `save!' 
    /Users/username/code/work/Jobber/db/migrate/20140317215526_rename_addons.rb:15:in `block in up' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/relation/batches.rb:26:in `block (2 levels) in find_each' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/relation/batches.rb:26:in `each' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/relation/batches.rb:26:in `block in find_each' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/relation/batches.rb:76:in `find_in_batches' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-deprecated_finders-1.0.3/lib/active_record/deprecated_finders/relation.rb:70:in `find_in_batches' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/relation/batches.rb:25:in `find_each' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/querying.rb:8:in `find_each' 
    /Users/username/code/work/Jobber/db/migrate/20140317215526_rename_addons.rb:13:in `up' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:578:in `exec_migration' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:559:in `block (2 levels) in migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:558:in `block in migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in `with_connection' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:557:in `migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:713:in `migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:963:in `block in execute_migration_in_transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `block in ddl_transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:221:in `within_new_transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/transactions.rb:209:in `transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `ddl_transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:962:in `execute_migration_in_transaction' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:924:in `block in migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `each' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:768:in `up' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/migration.rb:746:in `migrate' 
    /Users/username/.rvm/gems/ruby-2.1.1/gems/activerecord-4.0.4/lib/active_record/railties/databases.rake:42:in `block (2 levels) in <top (required)>' 
    /Users/username/.rvm/gems/ruby-2.1.1/bin/ruby_executable_hooks:15:in `eval' 
    /Users/username/.rvm/gems/ruby-2.1.1/bin/ruby_executable_hooks:15:in `<main>' 

任何人有什麼我做錯了任何想法，或東西我可以試試解決我的問題？

Answer 1

從.save改變！對.save幫表現出更好的錯誤消息，到底問題是與回調從

TableThing.find_each{|tt| 
    tt.column = tt.old_column 
    tt.save! 
    } 

所以改爲

TableThing.find_each{|tt| 
    tt.update_column(:column, tt.old_column) 
    } 

解決了這個問題。