Rename rake task to db:clear_empty_attributes and refactor to use all…

… tables by default

tasks/clear_empty_attributes.rake

@@ -1,17 +1,16 @@
-namespace :clear_empty_attributes do
-  desc "clear all blank strings of the given MODELS"
-  task :clear_all_blank_strings do
-    raise "rake clear_empty_attributes:clear_all_blank_strings MODELS=User,Movie,... to clear blank strings of those models" unless ENV['MODELS']
-    models = ENV['MODELS'].split(',').map(&:constantize)
-
-    models.each do |model|
-      puts "#{model}:"
-      model.columns.select(&:text?).each do |column|
+namespace :db do
+  desc "Clear all blank strings in the database. Specify TABLES=table1,table2 to limit to specific tables."
+  task :clear_empty_attributes => :environment do
+    connection = ActiveRecord::Base.connection
+    tables = ENV['TABLES'] ? ENV['TABLES'].split(/,/) : connection.tables
+    tables.each do |table|
+      puts "#{table}:"
+      connection.columns(table).select(&:text?).each do |column|
         name = column.name
         puts "  #{name}"
-        model.update_all("#{name} = NULL","#{name} = ''")
+        column_name = connection.quote_column_name(column.name)
+        connection.update("UPDATE #{connection.quote_table_name(table)} SET #{column_name} = NULL WHERE #{column_name} = ''")
       end
-      puts ''
     end
   end
 end