Three COM objects are necessary for transactions to occur between consumers and providers: data source, session, and enumerator.
The OLE DB connection model defines how data providers and service components are located and activated. Two objects are the basis for the OLE DB connection model: the data source object and the session. To access an OLE DB provider, a consumer must first create an instance of a data source object.
An enumerator is an object that can be used to search for the data source object rather than searching the registry directly. Once found, a session object is initialized, which then acts as a factory for transactions, commands, and rowsets. The primary function of a session is to define a transaction. A transaction is a mechanism used to define persistent units of work within an application, and to define how the different units relate to each other in a system with parallel activities.
| For more information on | Go to |
| COM (Component Object Model) | “Remote Data Access” in Chapter 1, “Overview of OLE DB” |
| Data providers and service components | “Consumers and Providers” in Chapter 1, “Overview of OLE DB” |
| Transactions | Chapter 12, “Transactions” |
| Consumers and providers | “Consumers and Providers” in Chapter 1, “Overview of OLE DB” |
| OLE DB connection model | “Data Source Objects and Session Objects” in Chapter 1, “Overview of OLE DB” |
| Data source object | “Data Source Objects" in this chapter |
| Session | “Sessions” in this chapter |
| Enumerator | “Enumerators” in this chapter |
| Rowsets | Chapter 4, “Rowsets” |