Chapter 12 - Designing and Implementing a Solution
Top-down design breaks down a complex system into smaller separate modules. Design tools include context diagrams, data flow diagrams, systems flowcharts, decision trees, decision tables and data dictionaries. A decision tree is a map showing the sequence of questions and answers that lead to a unique solution to a problem. A decision table is an alternative form of a decision tree. A data dictionary is a database that describes data. It identifies and organises the data used by information processing systems. An impementation plan describes how the new system will be introduced and how it will replace the old (current) system. Direct converion involves the complete replacement of the old system with the new at one single point in time. Parallel conversion involves operating the two systems for a period of time. Phased conversion involves the gradual implementation of components of a new system over a period of time.  Piolet conversion involves the introduction of the whole of the new system to a small aprt of the organisation.