SSADM uses a number of text and diagrams right through the whole life cycle of a system design, from the initial design idea to the actual physical design of the application. Structured Systems Analysis and Design Method are a discipline within the software development industry, seeking to provide a structure for capture and the activity, depot, dissemination of information aimed to make possible the economic development of computer systems that are suitable for aims and purpose (1)
Logical Data Modeling - first of all this is the process of identifying. Also it is the process of modeling and documenting the data requirements of the system being designed. The data is separated into entities (things about which a business needs to record information) and relationships (the associations between the entities). (2)
Data Flow Modeling - it is shows the process of identifying, modeling and documenting how data moves through a System of information. Data Flow Modeling examines processes (transform data from one form to another), data stores (the holding areas for data), external entities (sending data into a system or receives data from a system), and data flows (routes by which data can flow). (3)
All these three models gives us a different point of view on the same system, and each of it is required to ...