Is an index clustered or unclustered in Oracle?

Question

How can I determine if an Oracle index is clustered or unclustered?

I\'ve done

select FIELD from TABLE where rownum <100

where

Answer 1

Index Organized Tables have to be organized on the primary key. Where the primary key is a sequence generated value this is often useless or even counter-productive (because simultaneous inserts get into conflict for the same block).

Single table clusters can be used to group data with the same column value in the same database block(s). But they are not ordered.