The settings for specific versions of ODP.NET, can be configured in several ways for specific effects on precedence:
The Windows registry entries are machine-wide settings for a particular version of ODP.NET.
Windows registry based configuration is not supported for ODP.NET, Managed Driver.
The machine.config settings are .NET framework-wide settings that override the Windows registry values.
The application or web config file settings are application-specific settings that override the machine.config settings and the Windows registry settings.
Any attribute settings that are equivalent to the connection string override everything.
The application or web config file can be useful and sometimes essential in scenarios where more than one application on a computer use the same version of ODP.NET, but each application needs a different ODP.NET configuration. The Windows registry value settings for a given version of ODP.NET affect all the applications that use that version of ODP.NET. However, having ODP.NET configuration values in the application or web config file assure that these settings are applied only for that application, thus providing more granularities.
For example, if the application or web.config file has a StatementCacheSize configuration setting of 100, this application-specific setting forces the version of ODP.NET that is loaded by that application to use 100 for the StatementCacheSize and overrides any setting in the machine.config and in the registry. Note that for any setting that does not exist in a config file (machine.config or application/web config), the value in the registry for a loaded version of ODP.NET is used, as in previous releases.
Note that ODP.NET reads the machine.config files from the version of the .NET Framework on which ODP.NET runs, not from the version of ODP.NET.
ODP.NET only reads the Windows Registry and the XML configuration file when it is loaded into memory, thus any configuration changes made after that are not read or used until the application is re-started.
All Boolean attributes in ODP.NET .NET configuration settings accept true, false, 1, and 0 as valid values. 1 is equivalent to true and 0 is equivalent to false.