5、Side-by-Side Execution in ADO。NET

Side-by-side execution in the 。NET Framework is the ability to execute an application on a computer that has multiple versions of the 。NET Framework installed, exclusively using the version for which the application was compiled。 

An application compiled by using one version of the 。NET Framework can run on a different version of the 。NET Framework。 However, we recommend that you compile a version of the application for each installed version of the 。NET Framework, and run them separately。 In either scenario, you should be aware of changes in ADO。NET between releases that can affect the forward compatibility or backward compatibility of your application。 

Forward Compatibility and Backward Compatibility 

Forward compatibility means that an application can be compiled with an earlier version of the 。NET Framework, but will still run successfully on a later version of the 。NET Framework。 ADO。NET code written for the 。NET Framework version 1。1 is forward compatible with later versions。 

Backward compatibility means that an application is compiled for a newer version of the 。NET Framework, but continues to run on earlier versions of the 。NET Framework without any loss of functionality。 Of course, this will not be the case for features introduced in a new version of the 。NET Framework。 

The 。NET Framework Data Provider for ODBC 

Starting with version 1。1, the 。NET Framework Data Provider for ODBC (System。Data。Odbc) is included as a part of the 。NET Framework。 The ODBC data provider is available to 。NET Framework version 1。0 developers as a Web download from the Data Access and Storage Developer Center。 The namespace for the downloaded 。NET Framework Data Provider for ODBC is Microsoft。Data。Odbc。 

If you have an application developed for the 。NET Framework version 1。0 that uses the ODBC data provider to connect to your data source, and you want to run that application on the 。NET Framework version 1。1 or a later version, you must update the namespace for the ODBC data provider to System。Data。Odbc。 You then must recompile it for the newer version of the 。NET Framework。 

If you have an application developed for the 。NET Framework version 2。0 or later that uses the ODBC data provider to connect to your data source, and you want to run that application on the 。NET Framework version 1。0, you must download the ODBC data provider and install it on the 。NET Framework version 1。0 system。 You then must change the namespace for the ODBC data provider to Microsoft。Data。Odbc, and recompile the application for the 。NET Framework version 1。0。 

The 。NET Framework Data Provider for Oracle 

Starting with version 1。1, the 。NET Framework Data Provider for Oracle (System。Data。OracleClient) is included as a part of the 。NET Framework。 The data provider is available to 。NET Framework version 1。0 developers as a Web download from the Data Access and Storage Developer Center。 

If you have an application developed for the 。NET Framework version 2。0 or later that uses the data provider to connect to your data source, and you want to run that application on the 。NET Framework version 1。0, you must download the data provider and install it on the 。NET Framework version 1。0 system。 

Code Access Security 

The 。NET Framework data providers in the 。NET Framework version 1。0 (System。Data。SqlClient, System。Data。OleDb) are required to run with FullTrust permission。 Any attempt to use the 。NET Framework k data providers from the 。NET Framework version 1。0 in a zone with less than FullTrust permission causes a SecurityException。 

However, starting with the 。NET Framework version 2。0, all of the 。NET Framework data providers can be used in partially trusted zones。 In addition, a new security feature was added to the 。NET Framework data providers in the 。NET Framework version 1。1。 This feature enables you to restrict what connection strings can be used in a particular security zone。 You can also disable the use of blank passwords for a particular security zone。 For more information