Vince,
Thanks for your reply. Does instant client work in both 32bit and 64 bit? .I want to connect to oracle using .NET (programmetically) in custom Geoprocessing tool which is registered with ArcGIS 10.2 (32bit) and ArcGIS server 10.2 which is 64bit.
When I use Oracle.DataAccess.dll there is an compatibility issue between ArcGIS desktop, Server and Oracle libaries. Please throw some light on this. Thanks again.