Design notation
- 1. DESIGN NOTATION PRESENTED BY M.RAMYA. M.sc (CS&IT), NADAR SARASWATHI COLLEGE OF ARTS & SCIENCE, THENI.
- 2. INTRODUCTION • Good notation can clarify the interrelationships and interaction of interest. • Three level of design specifications: External design specification Architectural design specification Detailed design specification
- 3. • Notation used to specify the external characteristic , architectural structure and processing details of a software system include: Dataflow diagram Structure charts HIPO diagrams Procedure specification Pseudo code Structured flow charts
- 4. DATA-FLOW DIAGRAMS • Dataflow diagrams are directed graphs in which the nodes specify processing activities and the arcs specify the data items transmitted between processing nodes. • Dataflow diagram can be expressed using informal notation can be used to processing nodes , data sources , data sinks and data stores.
- 5. • Dataflow diagrams are excellent communicating with customer during requirements and analysis. • There are also used for representation of external and top level internal design specifications
- 6. Comput e C Comput e E Comput e D Transfo rm B Transfo rm A Input A Input B Operator Input Y Reference Data X Operator Input Z Output E Output D B’ A’ C AN INFORMAL DATA FLOW DIAGRAM OR “BUBBLED CHART”
- 7. STRUCTURED CHARTS • Structure chats are used to architectural design to document hierarchical structure , parameters and interconnection in a system . It differs from a flowchart in two ways: Structured chart has know decisions boxes. Sequential ordering of tasks
- 8. A ED H CB GF 1 2 3 4 5 6 7 8 INDICATE REPETITION FORMAT OF A STRUCTURE
- 9. HIPO DIAGRAMS • HIPO diagram(Hierarchy-process-input-output) were developed at IBM as design representation schemes for top- down software developed and external documentation aids for products. • HIPO diagram contains a visual table of contents, a set of overview diagram and set detail diagrams , it contains of a tree structured .
- 10. PROCEDURE TEMPLATE • The format of a procedure interface specification of architectural design , only information in level 1 need to supplied . The information on levels 2,3, and 4 can be included in successive steps. • It provides initial architectural design , specification of side effects , exception handling , processing algorithms and data representation.
- 11. PSEUDO CODE NOTATION • Pseudo code notation can be used in both the architectural and detailed design phases . • The designer describes system characteristics using short , concise , that are structured by keywords such as If-Then- Else , While-Do and End. • Pseudo code can replace flowcharts and reduce the amount of external documentations required to describe system.
- 12. STRUCTURED FLOWCHARTS • Flowcharts means are specifying and documenting algorithmic detailed in a software system. • Flowchart interoperate rectangular boxes for actions , diamond shaped boxes for decisions , directed arcs for interconnections for boxes. • Single entry , single exit allows hierarchical nesting of structured flowchart to design in top-down fashion.
- 13. S1; S2; P S F T WHILE P DO S; BASIC FORMS FOR STRUCTURED FLOWCHARTS
- 14. DECISION TABLES • Decision tables can be used to specify complex decision logic in a high level software specification. • There are useful for specifying algorithmic logic during detailed design. • Several preprocessor packages are available to translate decision tables into COBOL.
- 15. THANK YOU