BulkUpdatable: switch to using fetch for cast (#8)
BulkUpdatable: switch to using fetch for cast (#8)

While `string` and `text` are basically the default Postgres assumes, I
think it'll be better to have this be explicit, especially since all
other types are in the map. This will also help accommodate array type
columns, since we need to cast using `::string[]` or `::int[]` for
those.
mockdeep/junk_drawer,thread-pond/junk_drawer,thread-pond/junk_drawer,mockdeep/junk_drawer