In our recent note What is new for rquery December 2019 we mentioned an ugly processing pipeline that translates into SQL of varying size/quality depending on the query generator we use. In this note we try a near-relative of that query in the data_algebra.
The data_algebra package is a query generator that can act on either Pandas data frames or on SQL tables. This is discussed on the project site and the examples directory. In this note we will set up some technical terminology that will allow us to discuss some of the underlying design decisions. These are things that when they are done well, the user doesn’t have to think much about. Discussing such design decisions at length can obscure some of their charm, but we would like to point out some features here.