protected function validateDuplicates() {
    return (
      !$this->duplicatesExistForColumn($this->node->getQualifiedLeftColumnName()) &&
      !$this->duplicatesExistForColumn($this->node->getQualifiedRightColumnName())
    );
  }
protected function validateDuplicates() {
    return (
      !$this->duplicatesExistForColumn($this->node->getQualifiedLeftColumnName()) &&
      !$this->duplicatesExistForColumn($this->node->getQualifiedRightColumnName())
    );
  }
protected function validateDuplicates ( ) { return ( ! $ this -> duplicatesExistForColumn ( $ this -> node -> getQualifiedLeftColumnName ( ) ) && ! $ this -> duplicatesExistForColumn ( $ this -> node -> getQualifiedRightColumnName ( ) ) ) ; }
Checks that there are no duplicates for the `lft` and `rgt` columns.

@return boolean
Checks that there are no duplicates for the lft and rgt columns .