Zachman Framework

The Zachman Framework is one of the earliest and best-known approaches to enterprise architecture. It does not tell architects what steps to follow. Instead, it provides a structure for organizing every description of an organization, so that nothing important is missed and each description has a clear place. The framework arranges these descriptions in a grid: the columns ask six basic questions, and the rows represent the perspectives of different stakeholders, from executives defining scope to technicians building components.

The framework was introduced by John Zachman, then at IBM, in a 1987 article on information systems architecture, and has been refined several times since. It remains influential because its central idea, that a complex organization must be described from several perspectives and in answer to several questions, applies regardless of technology. For enterprise architecture and IT strategy, it is a useful checklist for completeness and a reminder that different audiences need different views of the same organization.

Definition of the Zachman Framework

The Zachman Framework is an ontology, or classification scheme, for the descriptive representations of an enterprise. It identifies 36 cells, each representing a distinct type of description, such as the business's main processes as seen by its owners or the data structures as specified by system designers.

Unlike TOGAF, it does not include a method for developing an architecture. Many organizations therefore use it alongside a method, as part of their chosen enterprise architecture framework.

The Six Columns

The columns correspond to six basic questions. What covers the things the organization deals with, such as data and inventory. How covers processes and functions.

Where covers locations and networks. Who covers people, roles and organization units.

When covers timing, events and cycles. Why covers motivation, including goals, strategies and business rules.

Each column is meant to be independent of the others, so that a description answers one question at a time. Combining answers across columns gives a complete picture.

The Six Rows

Each row represents a perspective. The top row describes the scope of the organization as seen by executives, and the second describes business concepts as seen by business management.

The third row describes system logic as seen by architects, and the fourth describes technology as seen by engineers.

The fifth row describes detailed components as seen by technicians, and the sixth describes the operating organization itself, the actual instances of data, processes and people.

Moving down the rows adds detail and constraints, from broad business intent to working systems.

Importance of the Zachman Framework in Enterprise Architecture

The framework provides a checklist for completeness. Teams can see which perspectives and questions their architecture work covers and which it leaves out.

It helps match descriptions to audiences. Executives need scope and business views, while engineers need technology and component views, and the grid makes these differences explicit.

It also encourages consistency. When each description has a defined place, it is easier to relate descriptions to each other and avoid duplicating effort. New team members can also find their way around existing architecture material more quickly when it follows a known structure.

Using Zachman Alongside Other Frameworks

Because it has no method, the Zachman Framework is often used to organize the outputs of other approaches. For example, an organization might follow TOGAF's development method and use the Zachman grid to check that its deliverables cover the necessary perspectives.

It can also help structure an architecture repository, with each artifact tagged by row and column so it can be found and reused.

Modeling languages such as ArchiMate can provide the notation for many of the descriptions the grid calls for.

This combination gives organizations a method, a classification and a notation, each from the approach that does it best.

Criticisms and Limitations

Critics note that filling all 36 cells for a large organization is impractical, and attempting it can produce documentation that few people use.

The framework gives no guidance on priorities, so organizations must decide for themselves which cells matter for their goals. Without that judgment, effort tends to go to the cells that are easiest to fill rather than those that matter most.

It also says little about governance, roadmaps or costs, which are central concerns for most architecture practices today. Organizations typically add these from other sources, such as target architecture planning and financial data.