Structure means arrangement of part.It means to put together things systematically in an optimized way.In simple word method is a regular way of doing things.Methodology is a system of methods.
SSADM,originally released as a methodology is a system approach to analysis and design of the information system.It is an open methodology based upon the waterfall model.It is used for large scale information projects.There are many CASE tools available to support this technique in software development.
Purpose: Formalize the requirement process and introduce best practice techniques.
Some of the important characteristics of SSADM are:
- Dividing a project into small modules with well defined objectives.
- Useful during requirements specification and system design stage.
- It uses combination of texts and diagrams.
- Simple and easily understood by clients and developers.
- Performing activities in sequence
There are three views of SSADM they are data processing and Events(time).The main techniques used in SSADM modeling are logical data modeling,data flow modeling and entity behavior modeling.
1.Logical Data Modeling:Involves the process of identifying,modeling and documenting data as part of system requirements and gathering.The datas are further divided into entities and relationship.
2.Data Flow Modeling:Involves tracing of data flow in the information system.It analyzes the process,data stores,external entities, and data movement.
3.Entity Behavior modeling:It involves identifying and documenting the events influencing the each entity and the sequence in which this event happens.
Objective of SSADM
SSADM was developed with the following objectives:
- Ensuring the project will still run after loss or damage
- Developed overall quality system
- Improve controlling and quality management of product
- make it possible for project to be supported by the computer based tools
- For improvement of communication between participants in a project so an effective framework is in place.
Stages of SSADM
The stages of SSADM are as follows:
Benefits of SSADM
- Timelines:Allows one to plan,manage,analyze and control the project.
- Usability:SSADM focuses more on the user need.Documentation is taken seriously and user requirements are taken the highest priority during the development.
- Effective use of skill:It doesn’t require very special skill.It can be easily be taught and learned.
- Higher productivity:It encourages delivery on time and with quality.It utlilises human resources properly thus increasing the productivity.
- Better quality:It reduces rate of errors at all the levels.
- Reduced cost:It reduces logical and physical design so the system doen’t have to be implemented again with new hardware or software.
Drawbacks of SSADM
- Organization needs large resources.
- Risk of over analyzing since SSADM mostly focuses on analysis part and documentation which can be time consuming.
Typical Tools and Techniques used in SSADM
- Activity Diagram
- Context Diagram
- ER diagram
- CASE tools
- Data Dictionaries
- Process Descriptors(decision table,flow charts,Structured English etc)