ASA Programming Guide
Three-Tier Computing and Distributed Transactions
Three-tier computing architecture
When client applications or application servers work with a single transaction processing database, such as Adaptive Server Anywhere, there is no need for transaction logic outside the database itself, but when working with multiple resource managers, transaction control must span the resources involved in the transaction. Application servers provide transaction logic to their client applications—guaranteeing that sets of operations are executed atomically.
Many transaction servers, including Sybase EAServer, use the Microsoft Distributed Transaction Coordinator (DTC) to provide transaction services to their client applications. DTC uses OLE transactions, which in turn use the two-phase commit protocol to coordinate transactions involving multiple resource managers. You must have DTC installed in order to use the features described in this chapter.
Adaptive Server Anywhere can take part in transactions coordinated by DTC, which means that you can use Adaptive Server Anywhere databases in distributed transactions using a transaction server such as Sybase EAServer or Microsoft Transaction Server. You can also use DTC directly in your applications to coordinate transactions across multiple resource managers.