> EDIT: I think I see the confusion. This project is about statistical classification, which generally assumes the data is in rows and columns. If I may come a

> EDIT: I think I see the confusion. This project is about statistical classification, which generally assumes the data is in rows and columns. If I may come at this from the other direction, do you mean the rows and columns of a matrix? Coming from a relational background, I hear "data", "row" and "column" and I'm thinking of something that is essentially meant to be a set of relations. > Can you be more specific? I'm not sure what you mean If your data is structured in a normal form, you can project it back out in a number of different ways. This is not true of most data structures, which entangle the structure of the world with the pattern of data access. Relational algebra allows a database to distinguish between the model of the world and how data may be arranged and accessed. The flipside of this is that relational algebra is performed over classical sets and, depending on one's views about sets, they can be used to represent anything that can be represented.