I just read a white paper by Steve Hoberman on Structured, Semi-Structured and Unstructured data. It immediately lead me to take this paradigm and apply it to each of the six unities. This gave me the following table:
For Datum, Steve gave the examples of a relational database for structured, a spreadsheet for semi-structured and a text document for unstructured.
I will be thinking about examples to fill in all the remaining cells.