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 form a ready model of the system being designed. This techniques are cross- concerned against each other to guarantee the readiness and exactness of the whole application. (4)
SSADM projects are broken down into five modules which are divided in future into a nomber of stages, tasks, steps:
Feasibility Study - Module 1 the feasibility study consists of only one stage. The business area is analyzed to determine whether a system can cost effectively support the business requirements.
Requirements Analysis -- Module 2 consists of 2 stages. Stage 1 is called the Investigation of Current Environment and Stage 2 is the Business System Options (BSO). First the requirements of the system are determined and then starting the modeling of the current business environment in terms of the processes carried out and the data structures involved. During stage 2 more then 6 models are investigated and as a result one of these models ore a hybrid solution is chosen. During this part 2 it is stipulated to support each business system option and the final chosen option. The transition from Stage 1 to Stage 2 of Module 2 is the main part of SSADM, this is these part in which the movement from a logical model of the current system to a logical model of the required system is carried out.
Requirements Specification -- Module 3 consists of a single stage. Here the future development of the work carried out, that was started in module 2. Detailed functional and non-functional requirements are determined and new techniques are presented to define the needed data structures and processing.
Logical System Specification -- Module 4 consists of 2 stages; Stage 4 it is Technical System Options and Stage 5 is the Logical Design. Here we have options of