Personally, I find it a bit questionable to pass implicitly numbered
parameters to SQL statement instead of explicitly named parameters. It
starts with things like this:

(sql-execute "insert into foo values (?, ?, ?, ?)"
              (list "Thing" -123 45.67 other-stuff))

And rapidly gets worse, especially with big WHERE clauses in selects etc.

Would it be possible to support named parameters only, or are there some
DB engines or scenarios where those don't fly?