code: function (cb) {
              return this.naked().ungraphed().singleRecord().chain(function (r) {
                  return r ? r[Object.keys(r)[0]] : null;
              }).classic(cb).promise();
          }
docs: Returns a promise resolved with the first value of the first record in the dataset.
  Returns null if dataset is empty.  Users should generally use
  {@link patio.Dataset#get} instead of this method.
  
  @example
  
  //'SELECT * FROM test LIMIT 1'
  DB.from("test").singleValue().chain(function(r) {
  //e.g r === 1
  });
  
  @param {Function} [cb] the callback to invoke when the action is done.
  
  @return {comb.Promise} a promise that will be resolved with the first value of the first row returned
  from the dataset.