module Sequel::Plugins::Composition::InstanceMethods

def _refresh(ds)

Clear the cached compositions when refreshing. 
def _refresh(ds)
  v = super
  compositions.clear
  v
end

def before_save

on the composition object.
For each composition, set the columns in the model class based 
def before_save
  @compositions.keys.each{|n| instance_eval(&model.compositions[n][:decomposer])} if @compositions
  super
end

def compositions

Cache of composition objects for this class. 
def compositions
  @compositions ||= {}
end