This is a list of things that should be done.
Help is welcome!

- Set parameters like NLS_DATE_FORMAT *after* the Oracle connection has been
  established.  Otherwise, an ill-guided Oracle logon trigger could mess up
  our NLS settings.

- Add an (unsafe!) option to use READ COMMITTED instead of SERIALIZABLE
  for Oracle transactions.  See issue #250.

- Add options "max_long", "sample_percent" and "prefetch" to
  IMPORT FOREIGN SCHEMA.  See issue #350.