I am intrigued by the site www.swivel.com and the way it handles data. It made me think about uploading pairs of data and organizing them in a nested tree. As an example data might be something as simple as a list of cities and their population. I then thought it would be good to have the data accessible in something like a directory. How far fetched would it be to have the data and it's directory structure in one or two tables? The columns would be id, parent id, data set name, data name and data value.