For the first time, I have to model data that is nothing more than a collection of statistics. The issue is that the same set of data are kept by category, for several categories. For example, for each category, I have to record quantity 1, quantity 2, and quantity 3. For each entity, I have to record the three quantities for category A, category B and category C. Here's my first cut at a model for a single entity:
This model makes me nervous. I don't really like introducing OneCategory, since its only purpose is to ensure that each category gets the same quantities recorded. I also don't like they way this maps to the relational model:
I was thinking more in terms of all the statistics residing in the "AllCategories" table.
Any thoughts? Are there some standard techniques for modeling this sort of data? I don't recall seeing an example of this in the Brown Book. Any thoughts on what I could improve would be very welcome.