Summary


This chapter may seem to have very little to do with software fortresses. In fact, however, transactional coordination is a major issue for software fortresses . Different technologies have different support for different flavors of transactions. The support that these technologies offer for transactions often influences our choice of which technologies to use in which fortress situations.

In a business application fortress, for example, it is important to be able to coordinate the work of different entities within a single, tightly coupled transaction, even when each of those entities is updating different transactional resources. Therefore, for a business application fortress we need intrafortress communication technologies that support tightly coupled multiple-resource transactions.

The main points of this chapter are these:

  • A transaction is a way of grouping together access requests to transactionally aware resources.

  • A transactionally aware resource is something that knows how to accept groups of updates and how to guarantee that those updates are done or not done en masse. A transactionally aware resource is often described simply as a transactional resource.

  • Tightly coupled single-resource transactions encompass only a single transactional resource.

  • Loosely coupled multiple-resource transactions encompass more than one transactional resource, but they do not attempt to coordinate their transactional updates across resources, although each individual resource coordinates its part of the transaction.

  • Tightly coupled multiple-resource transactions encompass more than one transactional resource and are coordinated across all of the transactional resources. These types of transactions require the help of a distributed transaction coordinator (DTC).

This chapter has introduced the fundamentals of transactions. I will expand on these basic concepts throughout the rest of the book.



Software Fortresses. Modeling Enterprise Architectures
Software Fortresses: Modeling Enterprise Architectures
ISBN: 0321166086
EAN: 2147483647
Year: 2003
Pages: 114

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net