COM & .NET Component Services

COM+ Transactions Architecture

COM+ is an advanced TPM that provides your components with easy-to-use administrative configuration for your transactional needs. COM+ encapsulates the underlying transaction monitoring and coordination required to manage a transaction. The COM+ transactions architecture defines a few basic concepts you need to understand to take advantage of COM+ transactions support: resource managers, the transaction root, the two-phase commit protocol, and the Distributed Transaction Coordinator (DTC).

Resource Managers

A resource (such as a database management system) that can participate in a COM+ transaction is called a resource manager. A resource manager knows how to conduct itself properly in the scope of a COM+ transaction—it records the changes done by your application’s objects and will only commit the changes when told to do so. A resource manager knows how to discard the changes and revert to its previous state if it is told to roll back. A resource manager can auto-enlist in a transaction—the resource manager can detect it is being accessed by a transaction and enlist itself in it. Every COM+ transaction has a unique transaction ID (a GUID), created by COM+ at the beginning of the transaction. The resource manager keeps track of the transaction ID and will not enlist twice. Auto-enlisting means that your components are not required to explicitly enlist the resources needed for a transaction; therefore, they do not have to deal with the problem of ...