result_id is a valid
result id returned by ifx_query() or
ifx_prepare().
Returns the number of rows affected by a query associated
with result_id.
For inserts, updates and deletes the number is the real
number (sqlerrd[2]) of affected rows. For selects it is an
estimate (sqlerrd[0]). Don't rely on it. The database server
can never return the actual number of rows that will be
returned by a SELECT because it has not even begun fetching
them at this stage (just after the "PREPARE" when the
optimizer has determined the query plan).
Useful after ifx_prepare() to limit queries to
reasonable result sets.
See also: ifx_num_rows()