Business application development exists as an increasingly complex process. Information technology managers and developers working for an organization that necessitates a business application are required to evaluate and implement appropriate application modeling strategies, software, database technologies and solution models. It is often conceivable that during the application development process, technologies, methodologies and development methods can drastically change, altered by a myriad of changes in each of these areas. The goal of the organization is to develop an application to support current business processes while simultaneously adopting technologies and methodologies that will remain forward compatible with new developments in the information technology field. Typically, one of the first applications an organization will develop is an application to facilitate the transactional nature of its business. A transactional application will often serve as a platform to accept business information from customers or clients, process this information and deliver a predefined product or service. An Online Transaction Processing (OLTP) application environment will accurately facilitate the development and operation of such an application.
The OLTP environment consists of several layers. The bottom-most layer in an OLTP environment consists of the data layer. The data layer or data tier is composed of all data required by the organization’s business needs to complete business transactions. The data tier can consist of legacy systems comprised of legacy data housed on mainframes, relational database data housed in SQL Server or Oracle, non-relational data such as Exchange Server data as well as other data, such as data supplied by accounting system software and other applications. The business logic tier consists of elements that employ business rules and logic to the data tier. The business logic tier maps business and organization rules and procedures to the transactional nature of the application. The business logic tier also is comprised of technologies that facilitate the transactional nature of the organizations business, such as Exchange Server, Internet Information Server and other application services. The presentation tier consists of the “thin” client portion of the transactional application. The presentation and business object tier, formerly deployed at the client together, then separated, now exists as a “window” to the actual business and data tiers. The presentation layer provides the client with a formatted view of the actual functionality of the business and data layers. The client, existing only as a mechanism to facilitate interaction of the user with the application is typically a small or “thin” deployment that can be implemented across a wide variety of platforms, including the Internet. Technologies such as Active Server Pages (ASP), VBScript, JavaScript and XML are designed to allow for the implementation of a thin client with rich functionality.
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courtesy Microsoft Windows DNA |
The Microsoft Windows DNA Architecture Illustrating the tiered solution model |
