add `bin/rake db:purge` task to empty the current database.

activerecord/CHANGELOG.md

+*   Add `bin/rake db:purge` task to empty the current database.
+
+    *Yves Senn*
+
 *   Deprecate `serialized_attributes` without replacement. You can access its
     behavior by going through the column's type object.
 

activerecord/lib/active_record/railties/databases.rake

@@ -28,6 +28,17 @@ db_namespace = namespace :db do
     ActiveRecord::Tasks::DatabaseTasks.drop_current
   end
 
+  namespace :purge do
+    task :all => :load_config do
+      ActiveRecord::Tasks::DatabaseTasks.purge_all
+    end
+  end
+
+  # desc "Empty the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config). Without RAILS_ENV it defaults to purging the development and test databases."
+  task :purge => [:load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.purge_current
+  end
+
   desc "Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)."
   task :migrate => [:environment, :load_config] do
     ActiveRecord::Migration.verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -143,6 +143,18 @@ def purge(configuration)
         class_for_adapter(configuration['adapter']).new(configuration).purge
       end
 
+      def purge_all
+        each_local_configuration { |configuration|
+          purge configuration
+        }
+      end
+
+      def purge_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          purge configuration
+        }
+      end
+
       def structure_dump(*arguments)
         configuration = arguments.first
         filename = arguments.delete_at 1

activerecord/test/cases/tasks/database_tasks_test.rb

@@ -285,6 +285,34 @@ class DatabaseTasksPurgeTest < ActiveRecord::TestCase
     end
   end
 
+  class DatabaseTasksPurgeCurrentTest < ActiveRecord::TestCase
+    def test_purges_current_environment_database
+      configurations = {
+        'development' => {'database' => 'dev-db'},
+        'test'        => {'database' => 'test-db'},
+        'production'  => {'database' => 'prod-db'}
+      }
+      ActiveRecord::Base.stubs(:configurations).returns(configurations)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:purge).
+        with('database' => 'prod-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge_current('production')
+    end
+  end
+
+  class DatabaseTasksPurgeAllTest < ActiveRecord::TestCase
+    def test_purge_all_local_configurations
+      configurations = {:development => {'database' => 'my-db'}}
+      ActiveRecord::Base.stubs(:configurations).returns(configurations)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:purge).
+        with('database' => 'my-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge_all
+    end
+  end
+
   class DatabaseTasksCharsetTest < ActiveRecord::TestCase
     include DatabaseTasksSetupper