Global Index

INSERT /*+ PARALLEL (storm_track97, 4) */ INTO storm_track97
SELECT /*+ PARALLEL (storm_track, 6) */ *
FROM storm_track
WHERE current_time < '01-JAN-98';

If a global index exists on the CURRENT_TIME column of the STORM_TRACK97 table, what will happen when this command is issued?

I know the result, it will fail because of Global Index but I don't know much about global index so Where can I find the information?

Also, which data dictionary will tell me the degree of parallelism?

Thanks.