pg_rename.rb

#!/usr/bin/env ruby
#
# Simple script to rename all columns/index/seq on rails app postgresql db
#
# Usage:  pg_rename foo bar
#
require 'rubygems'
require 'activerecord'
require 'annotate/annotate_models'
require 'config/boot'
require 'config/environment'

SUBJ = ARGV.delete_at(0)
NEWN = ARGV.delete_at(0)
SUBJP = SUBJ.pluralize
NEWNP = NEWN.pluralize

def get_all_and_migrate(files)
  out = { :up => [], :down => [] }
  files.each do |file|
    klass = AnnotateModels.get_model_class(file)
    next unless klass.respond_to? :columns
    klass.columns.each do |col|
      if col.name =~ /#{SUBJ}_id/
        out[:up]   << "    rename_column :#{klass.table_name}, :#{col.name}, :#{NEWN}_id"
        out[:down] << "    rename_column :#{klass.table_name}, :#{NEWN}_id, :#{col.name}"
      end
    end rescue nil

    indexes = klass.connection.indexes(klass.table_name)
    next if indexes.empty?
    indexes.each do |index|
      if index.name =~ /#{SUBJ}/
        new_name = index.name.gsub(Regexp.new(SUBJP),NEWNP)
        out[:up]   << "    rename_index  :#{index.name}, :#{new_name}"
        out[:down] << "    rename_index  :#{new_name}, :#{index.name}"
      end
    end
  end
  out
end

result = get_all_and_migrate(AnnotateModels.get_model_files) #.each { |k| get_and_print_columns k }
puts "Migration ----"
puts
puts '
# Monkeypatching...
module ActiveRecord
  module ConnectionAdapters
    class PostgreSQLAdapter
      def rename_index(old_index, new_index)
        execute "ALTER INDEX #{old_index} RENAME TO #{new_index};"
      end

      def rename_seq(old_seq, new_seq)
        execute "ALTER TABLE #{old_seq} RENAME TO #{new_seq}"
      end
    end
  end
end'

puts <<EOT
class BatchRename#{SUBJ.capitalize}To#{NEWN.capitalize} < ActiveRecord::Migration
  def self.up
    rename_table :#{SUBJP}, :#{NEWNP}
    rename_seq :#{SUBJP}_id_seq, :#{NEWNP}_id_seq

#{result[:up].join("\n")}
  end

  def self.down
    rename_table :#{NEWNP}, :#{SUBJP}
    rename_seq :#{NEWNP}_id_seq, :#{SUBJP}_id_seq

#{result[:down].join("\n")}
  end
end
EOT