Sets the number of rows to be prefetched after successful call to oci_execute(). The default value for rows is 1.
注: In PHP versions before 5.0.0 you must use ocisetprefetch() instead. This name still can be used, it was left as alias of oci_set_prefetch() for downwards compatability. This, however, is deprecated and not recommended.
如果成功则返回 TRUE，失败则返回 FALSE。