With a “few lines” of code Oracle is able to fetch WinCC OA values over XMLRPC webservice – current and history values (WinCC OA RDB-Manager is not needed).

WinCC OA values can be queried with “natural” Oracle SQL Statements

select t.dp, wccoa.dpGet(t.dp||'.int'), wccoa.dpGet(t.dp||'.int:_online.._stime')
from dpnames t where dp like 'Example%'

So, it is also easy to create “WinCC OA” (Web)APEX Applications!