Contents

# # This is a base class that uses ETL and Zach Dennis' excellent ar-
# # extensions gem.  To get the gem, just: 
# # 
# # sudo gem install ar-extensions
# # 
# # See:
# # http://www.igvita.com/2007/07/11/efficient-updates-data-import-in-rails/
# # http://agilewebdevelopment.com/plugins/ar_extensions
# # http://www.continuousthinking.com/
# 
# # To use this, 1) setup an extract to find the data, and 2) a transform to
# # create an array of arrays, with the first array as the header.  The
# # header and data should only contain values in the table to be imported.
# # The data_frame gem (sudo gem install davidrichards-data_frame)
# # may make the transform a LOT easier to do if there is a lot of column
# # munging to do.  Chris Wycoff's babel_icious gem will go a long way in
# # the transform if you have XML data you are working with 
# # (sudo gem install cwycoff-babel_icious).
# 
# class ActiveRecordLoader < ETL
#   
#   after_transform :ensure_array_of_arrays
#   before_load :ensure_class_defined
#   before_load :assert_header
#   
#   protected
#   
#     def ensure_array_of_arrays
#       # Not 100% whether I process raw_data before or after this method.  I think before.
#       data = @raw || @data
#       raise ArgumentError, 
#         "Expecting transformed data to be an array of arays" unless
#         data.is_a?(Array) and data.first.is_a?(Array) and data.last.is_a?(Array)
#     end
#     
#     def assert_header
#       @header ||= @data.shift
#       @header.symbolize_values!
#     end
#     
#     def ensure_class_defined
#       raise ArgumentError, 
#         "Must provide a class to import to.  Try #{self.to_a}.instance.options[:class] = ModelClassName" unless
#           self.options[:class]
#     end
#     
#     def load
#       options[:class].import(@header, @data)
#     end
# end

Version data entries

3 entries across 3 versions & 1 rubygems

Version	Path
davidrichards-etl-0.0.4	lib/etl/active_record_loader.rb
davidrichards-etl-0.0.5	lib/etl/active_record_loader.rb
davidrichards-etl-0.0.6	lib/etl/active_record_loader.rb