They shouldn’t be using DOUBLE, they should be using UNSIGNED INT (max 4,294,967,295). Not everyone appreciates the difference between integers and floats.
This is just the database table definitions (CREATE TABLE) and table definition changes (ALTER TABLE). There is no “code” that adjusts vote totals based on race.
It looks as though they are keeping track of blank votes (no selections made for any candidate for any position), undervotes (i.e. no selection made for President) and overvotes (i.e. more than one selection made for President), and they’re recording that by race, and summing it, presumably to determine voting competency by race.