/**
  *
  *
  * @return void
  */
 private function columns()
 {
     $sqlColumns = array();
     foreach ($this->entityMetadata->getColumns() as $column) {
         $sqlColumns[] = $this->connection->escapeAndQuoteField($column->getColumnName());
     }
     $this->sqlChunks[] = 'SELECT ' . join(', ', $sqlColumns);
 }