Oracle: Creating a Graphviz file showing object dependencies

with cur(owner_a, name_a, type_a,
         owner_b, name_b, type_b,
         lvl) as (
  select
     owner,
     object_name,
     object_type,
    cast(null as varchar2(128)),
    cast(null as varchar2(128)),
    cast(null as varchar2(  5)),
     0            lvl
  from
     dba_objects
  where
     owner       =     user             and
     object_type =    'TABLE'           and
     object_name like 'XYZ%'
                                  union all
  select
     nxt.owner  , nxt.name  , nxt.type  ,
     cur.owner_a, cur.name_a, cur.type_a,
     cur.lvl +1
  from
     cur                                                            join
     dba_dependencies nxt on nxt.referenced_owner = cur.owner_a and
                             nxt.referenced_name  = cur.name_a  and
                             nxt.referenced_type  = cur.type_a
     where
        nxt.type = 'VIEW'
)
search depth first by owner_a, name_a, type_a set order_by
select 'digraph D { node [ shape=box ]' x from dual
UNION ALL
select * from
(select distinct owner_a || '_' || replace(name_a, '$', 's') || ' [label="' || owner_a || '\n' || name_a || '\n' || type_a || '"]' x from cur union
 select distinct owner_b || '_' || replace(name_b, '$', 's') || ' [label="' || owner_b || '\n' || name_b || '\n' || type_b || '"]' x from cur where owner_b is not null
)
UNION ALL
select distinct x from (
select
   owner_b || '_' || replace(name_b, '$', 's') || ' -> ' ||
   owner_a || '_' || replace(name_a, '$', 's')                  x
from
   cur
where
   lvl > 0
)
UNION ALL
select '}' x from dual
;