INFO: Wizards Use CDataSource::OpenWithServiceComponents()

ID: Q190969

The information in this article applies to:

Microsoft Visual C++, 32-bit Editions, version 6.0

SUMMARY

CDatasource::OpenWithServiceComponents() was added to the OLE DB Templates late in the development stage and did not make it into the online documentation (it is documented in the Visual C++ 6.0 Readme).

OpenWithServiceComponents() was added to support the use of the OLE DB Service Components.

The ATL OLE DB Consumer Wizard may output code that uses CDatasource::OpenWithServiceComponents().

The MFC AppWizard, when using OLE DB support, always outputs code that uses CDatasource::OpenWithServiceComponents().

MORE INFORMATION

The OLE DB Service Components provide guaranteed functionality to OLE DB consumers above the minimum level required by OLE DB providers. The OLE DB 2.0 service components support:

Scrolling, Find, and bookmark support against any minimum-level OLE DB provider.

Updating against SQL providers.

Resource pooling for pooling connections in a frequent connect/disconnect scenario.

Automatic transaction enlistment in a Microsoft Transaction Server environment.

When using the MFC AppWizard with OLE DB support, a function C<ProjectName>Set::Open() is created. Within this function, a call to CDatasource::OpenWithServiceComponents() is made.

When using the ATL OLE DB Consumer Wizard, a function C<TableName>::OpenDataSource() is created. The following logic is used by the Consumer Wizard to determine whether CDataSource::Open() or CDataSource::OpenWithServiceComponents() is called from C<TableName>::OpenDataSource();.

The Wizard checks the provider to see if it supports IRowsetChange. If supported, the wizard generates code to call CDataSource::Open(). The OLE DB Service components are not required to obtain update functionality.

If the provider doesn't support IRowsetChange but does support SQL (the Wizard checks the DBPROP_SQLSUPPORT property of the DBPROPSET_DATASOURCEINFO property set), then the wizard generates code to call CDataSource::OpenWithServiceComponents(). The Service Components are required to obtain update functionality through SQL. The Microsoft Provider for Oracle is an example of such a provider.

If the provider doesn't support IRowsetChange and doesn't support SQL, then the wizard will not try to set any update properties. For 2 and 3, above, the wizard also generates a comment to explain what is happening.

REFERENCES

Visual C++ 6.0 Readme

Readmevc.htm can be found in the root directory of CD1 of Visual C++ 6.0 or Visual Studio 6.0.

Documents CDataSource::OpenWithServiceComponents().

OLE DB 2.0 Readme

Can be found as a menu item under the OLE DB 2.0 SDK menu and Olreadme.txt can be found in the DOC directory under the Data Access SDK directory. (for example, \msdasdk\doc\olreadme.txt).

The Data Access SDK can be installed from the \dasdk directory on CD2 of Visual C++ 6.0 or Visual Studio 6.0.

The OLE DB 2.0 readme contains the documentation for the OLE DB Service Components.

Additional query words: kbWizard kbATL kbDatabase kbOLEDB kbvc600


Keywords          : kbwizard kbATL kbDatabase kbOLEDB 
Version           : WINNT:6.0
Platform          : winnt 
Issue type        : kbinfo

Last Reviewed: August 3, 1999