sqlite3session_isempty —
Test if a changeset has recorded any changes.
int
sqlite3session_isempty(sqlite3_session
  *pSession);
Return non-zero if no changes to attached tables have been recorded by the
  session object passed as the first argument. Otherwise, if one or more changes
  have been recorded, return zero.
Even if this function returns zero, it is possible that calling
    sqlite3session_changeset() on the session handle may still return a
    changeset that contains no changes. This can happen when a row in an
    attached table is modified and then later on the original values are
    restored. However, if this function returns non-zero, then it is guaranteed
    that a call to sqlite3session_changeset() will return a changeset containing
    zero changes.