Information Systems Architecture in TOGAF ADM (Phase C)

The Information Systems Architecture phase in the ADM cycle focuses on the systems and data needed to support the business. It is divided into two parts:

Data Architecture: Defines how data is stored, managed, and shared across the organization.
Application Architecture: Identifies the applications required and how they interact to deliver business capabilities.

In simple terms, this phase answers:

"What data do we need, and how do we organize it?" (Data Architecture)
"What applications do we need, and how do they work together?" (Application Architecture)

Purpose of the Information Systems Architecture Phase

To ensure that the right data and applications are in place to support the Business Architecture (from Phase B).
To define the relationships between data and applications and their alignment with business processes.
To provide a foundation for the Technology Architecture (Phase D).

Outputs of the Information Systems Architecture Phase

1. Data Architecture Artifacts

Conceptual Data Model: High-level representation of the types of data used (e.g., customer, product, order).
Logical Data Model: Details of relationships between data entities.
Data Flow Diagram: Shows how data moves between systems and processes.
Data Management Policies: Guidelines for data governance, security, and quality.

2. Application Architecture Artifacts

Application Portfolio: List of current and future applications required to support the business.
Application Interaction Diagram: Visualizes how applications communicate and share data.
Application/Data Matrix: Maps applications to the data they use.
User Roles and Interfaces: Defines who interacts with each application and how.

3. Gap Analysis Results

Highlights missing or outdated applications, and inconsistencies in data management.

4. Updated Architecture Requirements:

Refined stakeholder needs based on analysis.

5. Baseline and Target Architectures:

Baseline: Existing data and application landscape.
Target: Desired state of data organization and application functionality.

Example in Simple Terms

Scenario: A hospital wants to create a seamless patient experience by integrating its systems.

Inputs:
- Business Architecture: "Provide patients with online appointment scheduling and medical record access."
- Current Systems: Separate systems for appointments, billing, and medical records.
- Stakeholder Requirements: Easy access to patient data for doctors and patients.
Activities:
- Data Architecture: Define the patient data needed, such as appointments, medical history, and billing info. Create a data flow diagram showing how this data is shared across systems.
- Application Architecture: Identify required applications like a patient portal, scheduling system, and billing system. Define how they integrate.
Outputs:
- Data Artifacts: A logical data model showing patient data relationships.
- Application Artifacts: Application interaction diagram showing the integration between systems.
- Gap Analysis: Current systems don’t communicate effectively; an integration platform is needed.