=> Both the 32-bit and 64-bit drivers can co-exist. A single User Data Source can be used for both 32-bit and 64-bit applications. This means they can be maintained with the default 64-bit ODBC Data Source Administrator. No more switching between the 32-bit and 64-bit ODBC Administrators.
Why does this work?
- The ODBC Data Source entries for the User DSN are stored in a shared location in the registry (HKCU/Software/ODBC). Items in this location are not redirected for 32-bit to the Wow6432Node tree.
- The ODBC Driver entries are stored in a redirectable location in the registry (HKLM/Software/ODBC). Items in this location redirect to the Wow6432Node tree (HKLM/Software/Wow6432Node/ODBC).
- The Driver names for both 32-bit and 64-bit entries are the same. Hence, applications will obtain the data source information from the shared location, then obtain the driver location from the redirectable entries.
- Whilst the Driver location is specified in the shared DSN entries, there is no reliance on that location. There is a fallback to the ODBC Driver entries in the registry.
The configuration
I have the 64-bit driver installed in c:\oracle\instantclient_11_2_64, and the 32-bit driver installed in c:\oracle\instantclient_11_2. The driver name is "Oracle in instantclient_11_2".
When doesn't it work?
This will not work for System Data Source entries as these are stored in the redirectable location (HKLM/Software/ODBC).
