code: protected function storeKeyValue($type, $data, $key = false, $comparison = false)
      {
          $dataMember = &$this->$type;
          // If array or object full of data was passed in, add all data
          // to appropriate data member.
          if (is_array($data) || is_object($data)) {
              foreach ($data as $item) {
                  array_push($dataMember, $item);
              }
          }
  
          // Add singular data item to data member.
          else {
              $item = array($key, $comparison, $data);
              array_push($dataMember, $item);
          }
      }
docs: For storing an array of data that represents an item.
  STORAGE FORMAT:
  [
  [column, operator, value],
  [name, LIKE, %s],
  [price, >, 100]
  ]