Data Access and Transactions
***** *Extending the Limits of Transactions
Although you can perform transactions using the ADO Connection object, the transaction is limited to a single server. In fact, most transaction processing systems allow only one server to participate in a transaction at a time.
But what if, for example, you are transferring money from checking accounts on two separate systems, and the systems use different database management systems? In this case, transaction protection limited to a single connection isnt enough. To manage both database operations as a single transaction, you need a distributed transaction coordinator like Component Services.
With Component Services, applications can easily use transactions that access multiple databases with true two-phase commit. The two-phase commit protocol ensures that transactions that apply to more than one server are completed on all servers or none at all. Two-phase commit is coordinated by the transaction manager and supported by resource managers.
Component Services supports a component-based programming model and run-time environment for developing and deploying enterprise Web server applications. You can configure components to run in the Component Services environment by adding them to a Component Services package. The packaged components run together in the same server process. Packages also define declarative security constructs that define how access to components is controlled at run time. With packages, developers and administrators can configure applications at deployment time to match the topology and security requirements of their target environment.