I've been sitting on this post for quite a while thinking I'd improve it enough to make it suitable for publishing. But that's not going to happen in the near term, so here it is in all its roughness.
Note: it's in SVG (I use Inkscape for sketching) which all modern browsers should render.
Tableau is superbly designed for accessing and analyzing tabular data. It's nearly as good at this as can be, notwithstanding the oddity here and there. It's almost trivially easy to connect to a table, or to more than one table using joins, custom SQL, and/or data blending, and to analyze the resulting flat record set that Tableau eventually sees.
It's simple and straightforward to organize the data, and to generate quantitative visualizations of it, and everything works smoothly. As long as the data falls within Tableau's data conceptual envelope. Once the data lies outside Tableau's horizon working with it isn't so easy, and in fact the same analytical operations that work well on simple tabular data may produce precise, arithmetically correct, and wrong results.
It would be very, very handy if Tableau grew to accommodate data that it doesn't now understand and provide an elegant user interface for analyzing. It need not, but it should, if it wants to keep it's leadership position.
This post covers the next step in expanding Tableau's data horizon: the simple, straightforward master-detail data structure.