Ciao, dai un'occhiata al "Adjacency List Model" o al "Nested Set Model"
http://en.wikipedia.org/wiki/Adjacency_list
http://en.wikipedia.org/wiki/Nested_set_model
http://dev.mysql.com/tech-resources/...ical-data.html
in italiano su html.it:
http://database.html.it/articoli/leg...e-su-database/