Enterprise Architecture Frameworks

What is enterprise architecture ? According to thought leaders in the field who are at Carnegie Mellon University it is defined as follows:--- A means of describing business structures and processes that connect business structures. The wiki definition addresses the how part very well An enterprise architecture (EA) is a rigorous description of the structure of an enterprise, its decomposition into subsystems, the relationships between the subsystems, the relationships with the external environment, the terminology to use, and the guiding principles for the design and evolution of an enterprise Roger sessions in his book on simplifying archiectures defines it to emphasize why EA is important. "An enterprise architecture is a description of the goals of an organization, how these goals are realised by business processes, and how these business processes can be better served through technology" In simpler words "EA is the art of maximizing the value of IT investments" I think this is best definition from the point of view of EA sponsor. Frameworks Framework is defined as "A structure for supporting or enclosing something else, especially a skeletal support used as the beasis for something being constructed; An external work platform; a scaffold; A fundamental structure, as for a written work; A set of assumptions.concepts,values, and practices that constitutes a way of viewing reality." There are three prominent frameworks popular in the academic and practitioner community. Zachman Framework, TOGAF and Fedeal Enterprise Architecture. Roger Sessions has proposed a SIP process that is a perspective that analyses complexity of the enterprise and helps built an architeture.

Zachman Framework

It is the most influential framework for designing enterprise architectures. It is actually a taxonomy for orgnizing architectural artifacts that take into account both whom the artifact targets ( business owner, engineer, CTO etc.) and what particular issue is being addressed.

Architectural artifacts are arranged in two dimensional grid. One dimension is the various players and the other is the descriptive focus of the artifact. The grid is attached as image.

There are 3 suggestions of the Zachman grid that can help the development of an enterprise architecture.

The first suggestion is every cell will have one and only one artifact and every artifact belongs to one and only one cell. If there is any ambiguity about the location of the artifact there is an issue with the artifact itself.

As and organizations starts accumulating artifacts to describe the enterprise architecture it can use the Zachman grid to clarify the focus of each of these artifacts. For example artifacts related to SAO will live in the third row that is designers perspetive.

The second suggestion is that an architecture is said to be complete if each and every cell of the grid has an artifact. This means there is sufficient artifacts to define the system from the perspective one player looking at one descriptive focus.

The last suggestion is that the cells in a column must be related to each other. Consider for example the data column. From business owners perspective data is information while from DBA's perspective data is tables and rows.

There has to be some way of relating this data with the database design that tables and indexes. Looking at the design one should be able to confirm that it is indeed driven by the requirements.