https://stackoverflow.com/questions/4048151/what-are-the-options-for-storing-hierarchical-data-in-a-relational-database https://stackoverflow.com/questions/4048

https://stackoverflow.com/questions/4048151/what-are-the-options-for-storing-hierarchical-data-in-a-relational-database https://stackoverflow.com/questions/4048151/what-are-the-opt...