sequel_auto_table_loader.rb

module SequelAutoTableLoader
  def method_missing(name, *args, &block)
    if name =~ /^#{self.class.const_get(:TABLE_PREFIX)}_/
      table_class_name = name.to_s.split(/_/).map(&:capitalize).join
      table_name = [table_class_name[0].downcase, table_class_name[1..-1]].join

      unless instance_variable_defined? "@#{name}"
        instance_variable_set(
          "@#{name}",
          self.class.const_get(table_class_name).send(
            name,
            self.send(self.class.const_get(:UNIQ_ID))
          )
        )
      end

      _yield instance_variable_get("@#{name}"), &block
    end
  end

  def self.included(class_or_module)
    class_or_module.define_singleton_method :const_missing do |table_class_name|
      table_class_name = table_class_name.to_s

      if table_class_name =~ /^#{class_or_module.const_get(:TABLE_PREFIX).capitalize}/
        first, *others = table_class_name.scan(/[A-Z][a-z]*/)
        table_name = [first.downcase, others.map(&:upcase)].join.to_sym

        singleton_method = table_class_name.scan(/[A-Z][a-z]*/).map(&:downcase).join("_").to_sym

        __uniq_id__ = class_or_module.const_get(:UNIQ_ID)

        table = Class.new(Sequel::Model(table_name))
        table.class_eval{
          define_singleton_method singleton_method do |_uniq_id|
            where(__uniq_id__ => _uniq_id).all
          end

          def method_missing(name, *args)
            column = DB.schema(self.class.table_name).find{|column, info|
              [column, name].map{|sym|
                sym.to_s.downcase.split(/_/).join
              }.inject(&:==)
            }

            if column
              send :[], column.first
            end
          end
        }

        const_set table_class_name, table
      end
    end
  end
end