Alternatively, you can use nested sets [1], optionally storing the hierarchy in a different table. Unless you're really interested in good write performance. 1

Alternatively, you can use nested sets [1], optionally storing the hierarchy in a different table. Unless you're really interested in good write performance. 1: http://en.wikipedia.org/wiki/Nested_set_model http://en.wikipedia.org/wiki/Nested_set_model