Whether you want to build your own forum, publish the messages from a mailing list on your Website, or write your own cms [1]: there will be a moment that you’ll want to store hierarchical data in a database. And, unless you’re using a XML [2]-like da
Most users at one time or another have dealt with hierarchical data in a SQL database and no doubt learned that the management of hierarchical data is not what a relational database is intended for. The tables of a relational database are not hierarchical