code: protected function buildUpdateSet()/*# : array */
      {
          $result = [];
  
          // build set
          $data = $this->clause_data[0];
          foreach ($data as $col => $val) {
              $result[] = $this->quote($col) . ' = ' . $this->processValue($val);
          }
  
          return $result;
      }
docs: Build SET ... = ..., ... = ...
  
  @return array
  @access protected