I've got a table which has a UNIQUE column:
CREATE TABLE groups (
id serial PRIMARY KEY,
name varchar(256) UNIQUE
When I make it into a class, like so:
_fromDatabase = True
Given that the name column is unique, it's useful and
possible to have the byName method be created, which,
in the absence of _fromDatabase, is done when a Col's
constructor has keyword argument alternateID.
Attached is a patch that does this for PostgreSQL.