Structured Systems Analysis and Design Method. SSADM with ConceptDraw DIAGRAM
Structured Systems Analysis and Design Method (SSADM) is the method which is used at projecting and analysis of information systems. This method was developed for government of Great Britain in the beginning of 80th of the past century. It was accepted as the national standard of Great Britain for information systems development in 1993. Thus SSADM usage is expedient for those who work with governmental organizations as this method is a standard for these organizations.
SSADM is based on the data flow diagrams. At the early stages of projecting at description of models (functional, informational and event-trigger) the top-down method is used.
At the description of data flows out of the system and into the system DFD, which denote boundaries of the system, are used.
At the description of data models LDS (Logical Data Structure) diagrams are used. LDS describes which data the system operates with. It is created for existing system and is added at the development of the new one.
For modelling events, happened in the system, ELN (Entity Life History) diagrams are used. These diagrams support states indications and the possibility of description not only consecutive but parallel or reiterative events and also description of the choice of events course.
ELN describes how data change in the system in the course of time at different variants of events.
Thus, the most important SSADM elements are flows modelling with the help of DFD, data logic modelling with the help of LDS and description of entities behavior.
Analysis, projecting and documenting of information system accordingly to SSADM involves 6 main stages.
Each stage is divided into several steps, which define tasks that should be fulfilled at the given stage. The system is studied for getting system requirements. Detailed project is created on the logic level and then transformed into physical project.
- Analysis of the existing system or estimation of practicability. It involves the analysis of the existing system and creation of DFD for visualization of known problems and system description. If the system is developed from the beginning than the projecting starts from definition of new system requirements.
- Requirements definition. On the basis of available data about the system new functions, which the system must execute are defined. Also boundaries of the future system and data which will be processed by the system are defined. Infological model of requirements is constructed.
- Definition of technical requirements and device equipment cost. Definition of the expected profit with the introduction of new functions.
- Development of logical data model. Specification of the list of functional requirements. After development of the logical project the adding of new requirements on SSADM is forbidden. Only correction of the existing requirements, their specification and concrete definition are allowed.
- Projecting of logical requirements. Specification of requirements.
- Physical projecting. Physical information model and specification to program elements are developed and optimized. Specifications to program elements are specified and documentation is drawn up.
The advantages of SSADM are the precise definition and support of so-called “non functional requirements”. Such requirements define the level of the quality with which the system must execute its functions. For example, access limitations, the mean time of lifelength to denial, time of the response, safety requirements, etc.
In comparison with other methods of information system projecting, particularly with E. Yordon and A. Young methods, SSADM is characterized with presence of clear consecution of steps at projecting.
Pic.1. Structured Systems Analysis and Design Method solution
The following features make ConceptDraw DIAGRAM the best Data Flow Diagram software:
- You don't need to be an artist to draw professional looking diagrams in a few minutes.
- Large quantity of ready-to-use vector objects makes your drawing diagrams quick and easy.
- Great number of predesigned templates and samples give you the good start for your own diagrams.
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NINE RELATED HOW TO's:
Structured-systems analysis and design method uses data flow diagrams to represent the process of data flowing through a system. Talking about this might be useless without a proper example of DFD for online store (Data Flow Diagram). This DFD example shows all the distinctness that a diagram can bring into a scattered data structure.
Data flow diagrams are used to show how data is processed within some business processes. Making DFD is a common practice for business process modeling and analysis. This diagram represents the online store business flow. It describes inputs and outputs within online selling process and depicts the interactions between its participants. This DF diagram can be used by system analysts to create an overview of a business, to study and discover its inherent strengths and weak points.
Picture: Example of DFD for Online Store (Data Flow Diagram)
This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the UML Class Diagram library of the Rapid UML Solution from the Software Development area of ConceptDraw Solution Park.
This sample describes the use of the classes, the generalization associations between them, the multiplicity of associations and constraints. Provided UML diagram is one of the examples set that are part of Rapid UML solution.
Picture: UML Class Diagram Generalization ExampleUML Diagrams
Database structures are usually described by ER-diagrams which represents entities as boxes with lines-connections between them. You can create any entity-relationship diagram (ERD) by means of ConceptDraw DIAGRAM using ready-to-use templates and special libraries containing all the needed symbols and shapes. Creating a model for your database from now on can take just a few minutes.
ERD (entity relationship diagram) designed to show the logical structure of databases. It intended to depict the relationships between data components (entities). ERDs are a popular tool for software engineers and architects. Using ERD they can manage the every aspect of database design. Also ERD can be used as guidelines for testing and communications before software release. This diagram represents the file reference system of the WordPress web platform. Because entity relationship diagrams have such a broad application area through the prevalence of database technology, it can be applied for a wide range of users.
Picture: Entity-Relationship Diagram (ERD) with ConceptDraw DIAGRAM
When trying to figure out the nature of the problems occurring within a project, there are many ways to develop such understanding. One of the most common ways to document processes for further improvement is to draw a process flowchart, which depicts the activities of the process arranged in sequential order — this is business process management. ConceptDraw DIAGRAM is business process mapping software with impressive range of productivity features for business process management and classic project management. This business process management software is helpful for many purposes from different payment processes, or manufacturing processes to chemical processes. Business process mapping flowcharts helps clarify the actual workflow of different people engaged in the same process. This samples were made with ConceptDraw DIAGRAM — business process mapping software for flowcharting and used as classic visio alternative because its briefly named "visio for mac" and for windows, this sort of software named the business process management tools.
This flowchart diagram shows a process flow of project management. The diagram that is presented here depicts the project life cycle that is basic for the most of project management methods. Breaking a project into phases allows to track it in the proper manner. Through separation on phases, the total workflow of a project is divided into some foreseeable components, thus making it easier to follow the project status. A project life cycle commonly includes: initiation, definition, design, development and implementation phases. Distinguished method to show parallel and interdependent processes, as well as project life cycle relationships. A flowchart diagram is often used as visual guide to project. For instance, it used by marketing project management software for visualizing stages of marketing activities or as project management workflow tools. Created with ConceptDraw DIAGRAM — business process mapping software which is flowcharting visio alternative or shortly its visio for mac, this sort of software platform often named the business process management tools.
Picture: Process Flowchart
Value Stream & Process Flow Diagramming Software is a very popular Lean Manufacturing tool that allows to see and visualize in details the company's processes and current state, the flow of material and information, and thus gives the possibility to analyze the efficiency of company's processes and then develop improved processes. Value stream maps are also a good way to define the steps that do not add value to the end product, in other words waste in a company's processes.
Picture: Value Stream & Process Flow Diagramming Software
A database is a data collection, structured into some conceptual model. Two most common approaches of developing data models are UML diagrams and ER-model diagrams. There are several notations of entity-relationship diagram symbols and their meaning is slightly different. Crow’s Foot notation is quite descriptive and easy to understand, meanwhile, the Chen notation is great for conceptual modeling.
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Picture: ERD Symbols and Meanings
Data flow diagrams are the graphical tool, used in the visualization of data flow of some data processing systems. It is the valuable process modeling tool. Also designing DFD is the important component of the initial part of any information system development project. The standard symbols are used to represent the interaction of a system components and how various kinds of components influence on data flow. The ConceptDraw Data Flow Diagrams solution is design to assist professional software engineers in making DFDs according to Gane and Sarson, and Yourdon and Coad notations.
Do you imagine yourself as a successful IT specialist? To your mind, they all use data flow diagram examples to learn and to get inspired. Aren’t you still with us?
Picture: Data Flow Diagram Examples
UML Diagrams Social Networking Sites Project. This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the UML Use Case Diagram library of the Rapid UML Solution from the Software Development area of ConceptDraw Solution Park.
This sample shows the Facebook Socio-health system and is used at the projection and creating of the social networking sites.
Picture: UML Use Case Diagram Example. Social Networking Sites Project