# $ 有什么特殊的含义?
create or replace view sys.user_col_comments as
select o.name, c.name, co.comment$
from sys.obj$ o, sys.col$ c, sys.com$ co
where o.owner# = userenv('SCHEMAID')
and o.type# in (2, 4)
and o.obj# = c.obj#
and c.obj# = co.obj#(+)
and c.intcol# = co.col#(+)
and bitand(c.property, 32) = 0 /* not hidden column */;