there is signature in the view dba_outlines,which says "Signature uniquely
identifying the outline SQL text"
It is self-explained, however, which column of v$sql does it correspond to.
there is a column EXACT_MATCHING_SIGNATURE,which is type of number.Obviously,
you can't join the view v$sql and dba_outlines tpgether by signature=
EXACT_MATCHING_SIGNATURE
.
