MDAC 2.5 SDK - Technical Articles
OLE DB service providers add features to existing data providers. Making a commonly used feature available externally to any data provider reduces the complexity of each provider and also eliminates redundancy of features among providers.
The functionality of service providers is further extended by the OLE DB Service Component Manager, a core component of the MDAC SDK, which enables or disables OLE DB services depending on the provider functionality required by the consumer. The Service Component Manager uses defaults set by the data provider in the registry. If the consumer uses the initialization component's IDataInitialize interface to invoke a data provider, all services are enabled by default. The consumer can override the defaults either in the connection string or by setting DBPROP_INIT_OLEDBSERVICES properties.
See the following topics for detailed information about the OLE DB service providers: