Information Systems Architecture (ISA) Conceptual blueprint for organization’s desired information systems structure Consists of (6Ws): Processes–data flow diagrams, process decomposition, etc. (DFD- Data Flow Diagram) Data (e.g. Enterprise Data Model–ER Diagram) Data Network–topology diagram (like Fig 1-9) People–people management using project management tools (Gantt charts, etc.) Events and points in time (when processes are performed. Use case diagram) Reasons for events and rules (e.g., decision tables) How What Where Who When Why

Data Flow Diagrams Data flow diagrams (DFDs) are graphical aids that describe an information system Advantages: freedom from committing to the technical implementation of the system too early. Further understanding the interrelatedness 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

Process External entities Data flows

Data store

Data Dictionary Data structure Data structure Data structure Program Modules

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

Example business function-to-data entity matrix (Fig. 2-3) Spot missing entity Higher priority