Having a side car HANA database doesn't stop you to consume its services from the abap layer . Please have a look into the beautiful log by Thomas below.
http://scn.sap.com/community/hana-in-memory/blog/2012/04/11/test
If you do not want to establish connection as described above, you do not have any choice other than to consumes exposed web services from ECC.
Sree