System design and Implementation NOTES.pptx

BCA V

1. PROCESS OF DESIGN System design  is the process of designing the elements of a system such as the architecture, modules and components, the different interfaces of those components and the data that goes through that system . System Analysis  is the process that decomposes a system into its component pieces for the purpose of defining how well those components interact to accomplish the set requirements.

2. ELEMENTS OF SYSTEM Architecture  - This is the conceptual model that defines the structure, behavior and more views of a system. We can use flowcharts to represent and illustrate the architecture. Modules -  This are components that handle one specific tasks in a system. A combination of the modules make up the system. Components -  This provides a particular function or group of related functions. They are made up of modules. Interfaces -  This is the shared boundary across which the components of a the system exchange information and relate. Data -  This the management of the information and data flow.

3. PROCESS OF DESIGN Process Design (or Process Mapping) is  a method for ensuring an efficient, maintainable and easily upgradeable software solution is found for your business process . It is comprised of: a relationship map; a cross functional process map; and a flow chart . INPUTS : System design takes the following inputs − Statement of work Requirement determination plan Current situation analysis Proposed system requirements including a conceptual data model, modified DFDs, and Metadata (data about data).

4. TYPES OF SYSTEM DESIGN Logical design pertains to an abstract representation of the data flow, inputs, and outputs of the system. It describes the inputs (sources), outputs (destinations), databases (data stores), procedures (data flows) all in a format that meets the user requirements . For example, the logical design for a relational DBMS includes the specifications for the relations (tables), relationships, and constraints (i.e., domain definitions, data validations, and security views ). A logical design is  a conceptual, abstract design .. The process of logical design involves arranging data into a series of logical relationships called entities and attributes.

5. PHYSICAL DESIGN A physical design focuses on specific solutions explaining how they are assembled or configured. It focuses on how data is entered into a system, verified, processed, and displayed as output . It produces the working system by defining the design specification that specifies exactly what the candidate system does. It is concerned with user interface design, process design, and data design.

6. CONTD.. Physical design represents the physical entities of your software system. Determining how a software system is packaged into its deployable units is a physical design issue. Determining which classes belong in which deployable units is also a physical design issue. For example, you can  abbreviate the column name that identifies employees, EMPLOYEE_NUMBER, to EMPNO .

7. COMPARISON USING AN EXAMPLE

8. PHYSICAL Physical design is where you translate the expected schemas into actual database structures. At this time, you have to map: Entities to Tables Relationships to Foreign Keys Attributes to Columns Primary Unique Identifiers to the Primary Key Unique Identifiers to Unique Keys

9. Design methodology A methodology is also defined as follows "  A method describes the activities involved in defining, building, and implementing a system ; a method is a framework. Since a method is a logical process for constructing systems (process), it is known as a metaprocess (a process for modeling processes). Design methodology refers to  the development of a system or method for a unique situation . Today, the term is most often applied to technological fields in reference to web design, software or information systems design.   A recommended collection of phases; procedures; rules; techniques; tools; documentation; management, and training to improve the quality of a software development effort.

10. Contd.. Improve productivity of analysis and programmers. Improve documentation and subsequent maintenance and enhancements. Improve communication among the user, analyst & designeer . Standarize approach to analysis and design.

11. Structured design It is a data flow based methodology . The approach begins with a system specification that identifies inputs and outputs ,describes functional aspects of the system. Ex : DFD,ER diagram From the DFD the next step in the definition of the modules and their relationship to one another in a form is called structure chart using data dictionary.

12. Contd … System specification DFD DATA DICTN STRUCTURE PROCESS INFORMATION PROCEED

13. FORMS DESIGN The data provide the basis for information system. Without data there is no system ,but data must be provided in the right form for input. The form is a tool with a message;it is the physical carrier of data – of information . A printed form is generally classified by what it does in the system .there are three primary classfication : action , memory and report forms.

14. Classification Action: orders,goes from one place to another. Memory: represents data,control details. Report:details that need attention,decision making , picture of project. Example : application form,purchase order. Journal sheet , purchase record, stock ledger. Balance sheet,operating statement , profit & loss

15. Requirements of form design Identification of wording. Maximum readability and use. Physical factors. Order of data items. Ease of data entry. Size and arrangement. Use of instructions. Efficiency considerations. Type of report.

16. Types of forms Flat form: it is a single copy form prepared on a paper. For additional copies of the original,carbon papers are inserted between copies. It is a simplest and inexpensive form to design ,print, which uses less volume.

17. Unit set form These are papers with one time carbons interleaved into unit sets for either handwritten or machine use. Carbons may be either blue or black ,standard medium intensity .Generally , blue carbons are best for handwritten forms while black carbons are best for machine use.

18. Continuous forms These multiple unit forms joined in a continuous strip between each pair of forms. It is less expensive method for large volume use.

19. INPUT DESIGN & OUTPUT DESIGN In an information system , input is the raw data that is processed to produce output. During the input design ,the developers must consider the input devices such as PC,MICR OMR. Well designed input forms have following properties: It should serve specific purpose effectively such as storing , recording and retrieving information. It ensures proper completion with accuracy. It should be easy to fill and straightforward. It should focus on user’s attention ,simplicity.

20. OUTPUT DESIGN The design of output is the most important task of any system. During output design , developers identify the type of outputs needed, consider necessary output controls. Objectives : To develop output design that serves the intended purpose and eliminates unwated output. To develop the output design meets the end users requirements. To deliver appropriate quantity of output. To make the output available on time for making good decisions.

21. Test plan The test plan is a base of every software testing .it is the most crucial activity which ensures availability of all lists of planned activities in an appropriate sequence. A test plan is detailed document which describes software testing areas and activities. It outlines the test strategy , objectives ,test schedule, required resources ,test estimation and test deliverables.

22. Contd.. Programmers usually do a better job in unit testing because they are expected to document and report on the method and extent of their testing . Users are involved , which means communication is improved between users and the designer group. Programmers are involved when they aware of user problems and expectations.

23. ACTIVITY NETWORK FOR SYSTEM TESTING Prepare test plan Specify condition for user acceptance testing Prepare test data for program testing Prepare test data for transaction path testing Plan user training Compile programs Prepare job performance aids Prepare operational documents

24. Prepare a test plan Outputs expected from the system Criteria for evaluating outputs A volume of test data Procedure for using test data Personnel and training requirements

25. Specify condition for user testing Planning for user acceptance testing calls for the analyst and the user to agree on the conditions for the test. Many of these conditions may be derived from the test plan. The start and termination dates for the test should also be specified in advance.

26. Prepare test data for program testing Test data prepared and documented to ensure that all aspects of the program are properly tested. After the testing ,the data are filed for future reference.

27. Transaction path testing This activity develop the data required for testing every condition and transaction to be introduced into the system. The test verifies that the test are virtually comparable to live data used after conversion.

28. Plan user training The system group has the time available to spend on training while the programs are being written. Initiating a user training program gives the systems group a clearer image of the user’s interest in the new system . A trained user participates more effectively in system testing.