module Sequel::DataObjects::Postgres::AdapterMethods

def execute(sql, args=nil)

a statement with the given sql and executes it.
Give the DataObjects adapter a direct execute method, which creates 
def execute(sql, args=nil)
  command = create_command(sql)
  begin
    if block_given?
      begin
        yield(reader = @db.log_yield(sql){command.execute_reader})
      ensure
        reader.close if reader
      end
    else
      @db.log_yield(sql){command.execute_non_query}
    end
  rescue ::DataObjects::Error => e
    @db.send(:raise_error, e)
  end
end

def single_value(reader)

DataObjects specific method of getting specific values from a result set. 
def single_value(reader)
  while(reader.next!) do
    return reader.values.at(0)
  end
end