Chapter 24. Transactions

In this chapter

Transactions Defined

Transaction Management

The COM+ Transaction Programming Model

Monitoring Transactions

Design Considerations

Performing transactions is one of the oldest challenges facing the computer industry. A tremendous percentage of the actual server-centric operations taking place in enterprise applications require the protection of transactions. At the onset, transaction technology was the domain of mainframes alone, but as critical applications have migrated to workstations and finally the PC platform, transactional technology has paved the way. In fact, transactions are the enabler for many of the most critical applications, making a platform with no transaction support a horror to such applications.

The .NET platform does not replace COM+. The COM+ Services are still required to build enterprise-class distributed applications. Microsoft added many new features to COM+ in Windows XP. The .NET Framework makes it easy to use the COM+ Services in your .NET applications. Managed components that use COM+ services are called Serviced Components .

COM+ supplies transaction services similar to those offered by traditional mainframe transaction processing monitors , as well as those found in the UNIX workstation world. The real beauty and uniqueness of COM+ has to do with the component nature of its framework. The COM foundation, upon which COM+ is built, makes constructing distributed component-based enterprise applications a dream. In Chapter 23, I discussed the basic nature of COM+ as a scalable, distributed component runtime environment. In this chapter, you'll learn about the mainframe-level reliability features afforded COM+ components through distributed transaction services.

The design goals for COM+ in .NET are simple:

• Support all the deployment and versioning improvements provided by the Common Language Runtime (CLR) while providing access to the COM+ services.

• Make all the COM+ Services available in a uniform way to all programming languages that support the CLR. Simplify the programming model.

• Make COM+ services easier to use, and integrate with Web Services.