I have recently installed QGIS 2.8 and Oracle 11.2 Client on Linux Red Hat 7.
Everything was fine, I am able to access Oracle database, as well as running QGIS. Unlike QGIS 2.8 from WIndows, Linux version does not have Add Oracle spatial layers and Oracle new connection icons. I think the Oracle support was removed by QGIS. Is this correct?
The machine where QGIS runs has installed Oracle Client 11g, unixODBC and SQL Developer. I have tested the oracle connectivity from a terminal windows as well as from SQL Developer and it works. I tried as alternative to load spatial data the followings: - cx_Oracle module from python: it connects to oracle from QGIS python console but cx_Oracle does not have functions to add SDO date to a QGIS layer. - Add vector layer from Database ODBC- does not connect to an Oracle