Overview of Representations
Representing an enterprise architecture eases the task of explanation. Representations of an enterprise architecture are based upon the perspectives required for effective decision-making. For instance, a stakeholder responsible for strategic business decisions will want to outline the business's mission, objectives, strategy, and tactics in a manner that is easily comprehensible to those responsible for implementing them. Similarly, representing business and technical analysis can pose challenges in demanding enterprise environments. This section provides a structure for enterprise architectures, based on the different levels of execution within the enterprise.
Fig.1: Enterprise Architecture: a layered view
1 Business Management Model
Business management models provide representations of strategy, prioritization, and selection, ideally through the identification of how minimal changes can produce the maximum value. Business management models can be used identify the required scope of an information system by identifying:
- things that are important to the business (mission, objectives, strategy, tactics)
- the processes the business performs
- the organizations important to the business
- significant events for the business.
For visually representing business management models, refer to value network analysis.
2 Business Information Model (Conceptual)
A business information model is a conceptual model that explains information the business requires to manage its processes and knowledge. The conceptual model is separated into the actions the business uses for its processes, and the resources, organizations, and structures used for fulfilling those processes. The conceptual model can be realized through people, systems, or people working with systems.
Fig.2: Business Information Model (Conceptual)
The business information model is a visual depiction of the business domain, independent of system designs. The business representation can be realized through a people interacting with an information system, an information system acting through pre-programmed / configured instructions, or people acting independently of an information system. The business representations allow an implementation to be realized as an optimal combination of these 3 approaches.
3 System Model (Logical)
The system model provides a specification of an information technology system. It defines user interaction with the system, the system's behaviour as a consequence of user interaction, and system's behaviour indenpdent of user interaction (automated tasks). The system model presents a vendor independent view, allowing the organization the flexibility to make vendor choices without any analysis bias.
Fig.3: System Model (Logical)
The system model is a logical model that provides an implementation and vendor independent representation of an information system. The system model specifies how users will interact with the information system and the system's behavior as a consequence of user interaction. It also specifies the system's behavior independent of user interaction.
4 Implementation Model (Technical)
The technical model provides an implementation specfication for the construction of a system. It identifies the system's architecture, and how each of those architectural components will function. It also identifies a development structure, outlining the how the source code will be developed and structured.
Fig.4: Implementation Model (Technical)
The system architecture provides the structure for the different layers of responsibility within the application. An example is provided for a system architecture for a web-based information system.
The services architecture provides the structure of enterprise services used by the application. Service-oriented architecture (SOA) principles can be applied to model the organization's internal services (those services used to fulfill intra-organizational capability) and external services (those services used to provide customers and trading partners with functionality required to fulfill inter-organizational capability.
The data architecture is an example of the structure used within an relational database manage system (RDBMS). The domain model is used to model the entities within the business domain. The interaction model is used to illustrate a dynamic view of the lifecycle of a service request.
5 Realized System
Finally, a system is realized such as an ERP or CRM system. It is important to go through the lifecycle of business information and system modeling in order to ensure that the realized system is inline with immediate business needs (tactical), capable of managing change for future business demands (strategic), and is able to contribute towards business growth through being an asset to the organization, and not a limitation.
