Structured Systems Analysis and Design Methodology (SSADM)
Introduction
Structured Systems Analysis and Design Methodology (SSADM) is an integrated set of standards and guides for the analysis and design of computer systems (1). SSADM is used in the analysis and design stages of system development. SSADM does not cover the construction, testing and implementation of software. Because the rigid structure of the methodology, SSADM is praised for it’s control over projects and it’s ability to develop better quality systems. SSADM is an open standard and is freely available.
History
1980 Central Computer and Telecommunications Agency (CCTA) evaluate analysis and design methods.
1981 LBMS method chosen from shortlist of five.
1983 SSADM made mandatory for all new information system developments
1984 Version 2 of SSADM released
1986 Version 3 of SSADM released, adopted by NCC
1988 SSADM Certificate of Proficiency launched, SSADM promoted as ‘open’ standard
1989 Moves towards Euromethod, launch of CASE products certification scheme
1990 Version 4 launched
1993 SSADM V4 Standard and Tools Conformance Scheme Launched
1995 SSADM V4+ announced, V4.2 launched
Stages
SSADM consists of 5 main stages (which are broken-down in several sub-stages). The 5 main stages are:
Feasibility Study:
The Feasibility Study involves a high level analysis of a business area to determine whether it’s feasible develop a particular system. Data Flow Modeling and (high-level) Logical Data Modeling can be used as technique during this stage.
Requirements Analysis:
In the Requirements Analysis stage requirements are identified and the current business environment is modeled, business system options are produced and presented. One of these options will be chosen en refined. Data Flow Modeling and Logical Data Modeling can be used as technique during this stage.
Requirements Specification:
In the Requirements Specification the functional and non-functional requirements are specified as a result of the previous stage. Data Flow Modeling, Logical Data Modeling and Entity Event Modeling can be used as technique during this stage.
Logical System Specification:
In the Logical System Specification the development and implementation environment are specified, and the logical design of update and enquiry processing and system dialogues are carried out.
Physical Design:
During the Physical Design the logical system specification and technical specification are used to create a physical design and a set program specifications.
Techniques
There are 3 key techniques used in SSADM, namely:
Logical Data Modeling: This is the process of identifying, modeling and documenting the data requirements of a business information system (3). More on Logical Data Modeling at: [1].
Data Flow Modeling: This is the process of identifying, modeling and documenting how data flows around a business information system (3). More on Data Flow Modeling at: [2].
Entity Event Modeling: This is the process of identifying, modeling and documenting the business events which affect each entity and the sequence in which these events occur (3). More on Entity Event Modeling at: [3].