Chapter 12 ndash; Systems DesignObjectives.ppt

Chapter 12 – Systems DesignObjectives: Describe the design phase in terms of your information building blocks. Identify and differentiate between several systems design strategies. Describe the design phase tasks in terms of a computer-based solution for an in-house development project. Describe the design phase in terms of a computer-based solution involving procurement of a commercial systems software solution. System Design Systems design – the specification of a detailed computer-based solution. Also called physical design. systems analysis emphasizes the business problem systems design emphasizes the technical or implementation concerns of the system. System Design Approaches Model-Driven Modern structured design Information engineering Prototyping Object-oriented RAD JAD Model-Driven Approaches Model-driven strategy – a system design approach that emphasizes drawing system models to document technical and implementation aspects of a system. Model-Driven Approaches – Modern Structured Design Modern structured design – a system design technique that decomposes the system’s processes into manageable components. Synonyms (although technically inaccurate) are top-down program design and structured programming. Design in a top-down hierarchy of modules Easier to implement and maintain (change). Modules should be highly cohesive Accomplish one function only Modules should be loosely coupled Minimally dependent on one another Structure Chart Model-Driven Approaches – Information Engineering Information engineering (IE) – a model-driven and data-centered, but process-sensitive technique for planning, analyzing, and designing information systems. IE models are pictures that illustrate and synchronize the system’s data and processes. The primary tool of IE is a data model diagram. Physical Entity Relationship Diagram Model-Driven Approaches – Prototyping Prototype – a small-scale, incomplete, but working sample of a desired system Iterative process invol