Information Systems Architecture (ISA)


Information Systems Architecture (ISA)

Conceptual blueprint for organization’s desired information systems structure

Consists of:

 Data (e.g. Enterprise Data Model – simplified ER



Processes – data flow diagrams, process decomposition, etc. (DFD- Data Flow Diagram)

Data Network – topology diagram (like Fig 1-9) Where


 People – people management using project management tools (Gantt charts, etc.)


 Events and points in time (when processes are performed)


 Reasons for events and rules (e.g., decision tables)


Data Flow Diagrams

 Data flow diagrams (DFDs) are graphical aids that describe an information system

 DFDs represent a logical model that shows what a system does, not how it does it

 Advantages:

 freedom from committing to the technical implementation of the system too early.

 Further understanding the interralatedness of systems and subsystems.

 communicating current system knowledge to users


Data Flow Diagrams

 Data flow diagram symbols

 Four basic symbols

 Process

 Data flow

 Data store

 External entity

External entities


Data flows

Data store

Data Dictionary

Develop Enterprise Model

 Functional decomposition

 Iterative process breaking system description into finer and finer detail

 Enterprise data model

 Planning matrixes

 Describe interrelationships between planning objects

Figure 2-2 Example of process decomposition of an order fulfillment function (Pine Valley Furniture)

Decomposition = breaking large tasks into smaller tasks in a hierarchical structure chart

Higher priority business function-to-data entity matrix

Spot missing entity