Developing MIS System

1. Developing MIS System

2. Question paper • What is BPR? How IT is an enabler for BPR? • What is Brick and Mortar ?How Virtual companies are different from Brick and Mortar business? • How IT helps in becoming the Agile company? • What is SDLC?What are the steps involved in SDLC? • What is maintenance and its types? • What is Testing ? Difference between White box and Black box testing? • What is Predictive and Adaptive approach for software development with example? • What is Waterfall model?

3. System Development Life Cycle • SDLC (System Development Life Cycle) is defined as the process (as a whole) of developing system or software to meet certain requirements. • It covers many activities • Understanding why the system should be built, • Studying the project feasibility, • analyzing problems, • choosing the system design and architecture, implementing and testing it, • up to delivering the system as product to the user.

4. The systems development life cycle (SDLC) is a conceptual model used in project management that describes the stages involved in an information system development project.

5. Phases of SDLC • System development life cycle (SDLC). includes six steps • investigation, • analysis, • design, • development, • implementation and • maintenance.

6. SDLC Methodology • The existing system is evaluated. Deficiencies are identified. This can be done by interviewing users of the system and consulting with support personnel. • The new system requirements are defined. In particular, the deficiencies in the existing system must be addressed with specific proposals for improvement. • The proposed system is designed. Plans are laid out concerning the physical construction, hardware, operating systems, programming, communications, and security issues.

7. SDLC Methodology Contd.. • The new system is developed. The new components and programs must be obtained and installed. Users of the system must be trained in its use, and all aspects of performance must be tested. If necessary, adjustments must be made at this stage. • The system is put into use. This can be done in various ways. The new system can phased in, according to application or location, and the old system gradually replaced. In some cases, it may be more cost-effective to shut down the old system and implement the new system all at once. • Once the new system is up and running for a while, it should be exhaustively evaluated. Maintenance must be kept up rigorously at all times. Users of the system should be kept up-to-date concerning the latest modifications and procedures.

8. Phases of SDLC

9. Investigation Phase • System Investigation :What is the Fault in the System? • Preliminary Analysis • Determining the nature and scope of the problems to be solved is carried out. • Possible solutions are proposed, • Feasibility Study is carried out Here are some possible definitions of problems:1. The existing system has a poor response time, i.e. it is slow.2. It is unable to handle workload.3. The problem of cost, i.e. the existing system is not economical.4. The problem of accuracy and reliability.5. The requisite information is not produced by the existing system.6. The problem of security. Key Activities • Conduct preliminary investigation/feasibility study • Determine scope of problem/project • Identify constraints to systems development • Identify resources required

10. Feasibility Study • The feasibility of a proposed system can be assessed in terms of four major categories, as summarized below.1. Organizational Feasibility: the extent to which a proposed information system supports the objective of the organization.2. Economic Feasibility: is the cost benefit analysis.In this study, costs and returns are evaluated to know whether returns justify the investment in the system project. (a) The cost of conducting a full system investigation.(b) The cost of hardware and software for the class of application being considered.(c) The benefits in the form of reduced costs, improved customer service, improved resource utilization or fewer costly errors.

11. 3. Technical Feasibility: whether reliable hardware and software resources required to meet the needs of the proposed system can be acquired or developed by the organization in the required time. • 4. Operational Feasibility: the willingness and the ability of the management, employees, customers, suppliers, etc., to operate, use and support a proposed system.

12. Analysis Phase/Requirement definition Phase • The aim of this phase is to document the existing user functions, processes, activities and data. • The analyst understands the type of information and the nature of the functions required for the propose system. The analyst makes a brief survey of the requirements and tries to analyze the performance of the system which is to be developed. Key Activities • Gather business requirements • Build trust and rapport with users • Document the existing system • Develop preliminary data and process models • Verify requirements and current system/procedures with users

13. How to get information • Direct observation • Interviews (individual and groups, structured and unstructured) • Questionares • Surveys • Records • Observations • Activity logs/work diaries

14. Requirements • User Interface Requirement • Processing Requirements • Storage Requirements • Control requirements Output of analysis phase is System requirement specification, a requirements specification for a software system, is a complete description of the behavior of a system to be developed and may include a set of use cases that describe interactions the users will have with the software.

15. Flow Charts • A system flow chart, or data flow chart, is used to describe the flow of data through a complete data-processing system. Different graphic symbols represent the clerical operations involved and the different input, storage, and output equipment required. Although the flow chart may indicate the specific programs used, no details are given of how the programs process the data. In other words, it's like a DFD. • A program flow chart is used to describe the flow of data through a particular computer program, showing the exact sequence of operations performed by that program in order to process the data. Different graphic symbols are used to represent data input and output, decisions, branches, and subroutines.

17. Design Phase • Objective of the design phase is to create a design that satisfies the agreed software requirements. Successful completion of the Design Phase should comprise: • Transformation of all requirements into detailed specifications covering all aspects of the system • Approval to progress to the Development Phase

18. System Design Phase • Data structure (e.g. field names, data types and lengths, filenaming, folder structure schemes etc • How the data is to be acquired (what procedures and equipment will be needed?)  • Data input procedures and equipment (e.g. keyboard? barcode reader? ICR/OMR?)  • Interfaces (e.g. what will a data entry screen look like? Will people need to leave the main screen to access functions? How will menus be organised into commands and submenus? What shortcut keys will be used? Will you use a text box, listbox, combo box, tickbox for a particular item of data entry? What colour scheme will be used? What navigation scheme will be used? What icons represent what meaning? Will the layout of the data entry form help users enter data in the required order and the required format? Control procedures - What validation rules will be used on what fields to check for data reasonableness, existence or format?) What will different error messages say? • What workloads and capacities the system must be capable of - e.g. storage capacities, number of transactions per hour, disaster-recovery abilities  • Documentation and training requirements for different types of users  • Validation and storage methods to be used   • Backup requirements and procedures - what needs to be backed up, how often, how backups are stored, what backup scheme will be used? 

19. Tools for System Design • A data flow diagram is used to describe the flow of data through a complete data-processing system. • Different graphic symbols are used to represent input, process ,storage, and output. • Flow chart may indicate the specific programs used, no details are given of how the programs process the data.  • Gantt Charts is detailed timeline of events in a project laid out. • Structure chart consist of a top-down description of a process and its sub-processes. • Data Dictionary - describes (for example) a database's fields, types, lengths, validation rules, formulae.

20. Development phase • The design must be translated into a machine-readable form. • The code generation step performs this task. If the design is performed in a detailed manner, code generation can be accomplished without much complication. • Programming tools like compilers, interpreters, debuggers etc. are used to generate the code. • Different high level programming languages like C, C++, Pascal, Java are used for coding.

21. Testing Phase • Software testing is the process of checking software, to verify that it satisfies its requirements and to detect errors.Software testing methods are traditionally divided into black box testing and white box testing.Black box testingBlack box testing treats the software as a black-box without any understanding of internal behavior. It aims to test the functionality according to the requirements. Thus, the tester inputs data and only sees the output from the test object. White box testingWhite box testing, however, is when the tester has access to the internal data structures and algorithms.

22. Implementation Phase In SDLC, implementation refers to post-development process of guiding to use the system. This includes customizations, Systems Integrations, User Policies, User Training and Delivery.Software Implementations involve several professionals like Business Analysts, Technical Analysts, Solution Architect , and Project Managers. Analysts in the implementation phase acts as the intermediator between user and developers. The Implementation Phase includes:  Hardware and software installation User Training Documentation

23. Implementation • Deploying of new system in its target environment. The purpose of the Implementation Phase is to deploy and enable operations of the new information system in the production environment.

24. Types of Implementation • Direct Approach:Installation of new system and the immediate discontinuation of old system.Sometimes called Cut off.This approach produces rime gap when no system is working. • Parallel Approach:The new system is installed and operated in parallel with the current system untill it has been tested throughly. • It is the opposite of the direct implementation approach. • It is costly because of duplicating facelities and personnel to maintain the dual system. • Advantage is the accuracy of the system. • Modular Approach:”Pilot Approach” refers to implementation of a system in the organisation on a module basis.forexample:an inventory system might be implemented with only selected product grouping or with all the products on one location of multiple location oreganisation. • Advantages • The risk of system failure is localised • The problem is identified in the system can be corrected before further implementation. • Other operating personnel can be trained in a live environment before the system is implemented at their location. • Phase-in Approach:”Cut over by segments” which is similar to the modular approach. The only difference is the system itself is segmented and not the organisation.

25. Maintenance • Maintenance includes all the activity after the installation of software that is performed to keep the system operational.

26. Types of Maintenance • System maintenance is an ongoing activity, which covers a wide variety of activities, including removing program and design errors, updating documentation and test data and updating user support. For the purpose of convenience, Maintenance may be categorized into three classes, namely i) Corrective, ii) Adaptive, and iii)Perfective. Corrective Maintenance: - Corrective maintenance refers to action only taken when a system or component failure has occurred. • This type of maintenance implies removing errors in a program, which might have crept in the system due to faulty design or wrong assumptions.

27. Adaptive Maintenance: - In adaptive maintenance, program functions are changed to enable the information system to satisfy the information needs of the user. This type of maintenance occurs due to organizational changes which may include: a) Change in the organizational procedures, b) Change in organizational objectives, goals, policies, etc. c) Change in forms, d) Change in information needs of managers. e) Change in system controls and security needs, etc. Perfective Maintenance: - Perfective maintenance means adding new programs or modifying the existing programs to enhance the performance of the information system. • To respond to user’s additional needs which may be due to the changes within or outside of the organization. • Outside changes are primarily environmental changes that include: a) Changes in governmental policies,laws, etc., b) Economic and competitive conditions, and c) New technology.

28. Data Flow diagrams Graphical representation of the logical flow of data. It is also know as bubble chart. A DFD consists of a series of bubbles joined by lines representing data flow in the system. • Square: Represents the source and destination of system data. • Arrow: It represents the data flow. • Circle or Bubble: Represents a process that transforms incoming data flow into outgoing data flow. • Open Rectangle: Represents a data store.

29. Rules for DFD • Process should be named and numbered • The direction of flow is from top to bottom and from left to right. • When a process is exploded into lower levels they are numbered properly.e.g-5 can be exploded in 5.1,5.2.. • The name of data stores, source and destinations are written in capital letters.

30. ER Diagrams •  A graphical representation of entities and their relationships to each other. It is used in organization of data within databases. The elements of an ERD are: • Entities are the "things" for which we want to store information. An entity is a person, place, thing or event. • Attributes are the data we want to collect for an entity. • Relationships describe the relations between the entities.

31. A relationship is how the data is shared between entities. There are three types of relationships • 1. One-to-One • For example, in a database of employees, each employee name (A) is associated with only one social security number (B).

32. One to Many • For example, for a company with all employees working in one building, the building name (A) is associated with many different employees (B), but those employees all share the same singular association with entity A. •  Many-to-Many • For example, for a company in which all of its employees work on multiple projects, each instance of an employee (A) is associated with many instances of a project (B), and at the same time, each instance of a project (B) has multiple employees (A) associated with it.

33. Relationships

37. Decision Tree • Graphical representation of a sequence of decisions and actions. • The decision tree represents various conditions and actions that resembles branches of a tree that why it is called decision tree.

38. Example • A computer firm offers the following discount policy to its customers • If payment is made within 10 days • 3% discount is allowed on orders above Rs 10000 • 2% for orders between 5000 to 10000 • 1% for orders upto 5000 • However if the payment is made more than 10 days than no discount is allowed.

39. Objectives of SDLC • An SDLC has three primary business objectives:- Ensure the delivery of high quality systems;- Provide strong management controls;- Maximize productivity.

40. Waterfall Model • In "The Waterfall" approach, the whole process of software development is divided into separate process phases. • The phases in Waterfall model are: Requirement Specifications phase, Software Design, Implementation and Testing & Maintenance. • All these phases are cascaded to each other so that second phase is started as and when defined set of goals are achieved for first phase and it is signed off, so the name "Waterfall Model".

41. Waterfall Model

42. Phases of waterfall maodel • Requirement Analysis and Definition • All possible requirements of the system to be developed are captured in this phase. • Requirements are a set of functions and constraints that the end user (who will be using the system) expects from the system. • The requirements are gathered from the end user are analyzed for their validity, and the possibility of incorporating the requirements in the system to be developed is also studied. • Finally, a requirement specification document is created which serves the purpose of guideline for the next phase of the model. • System and Software Design • The requirement specifications from the first phase are studied in this phase and a system design is prepared. • System design helps in specifying hardware and system requirements and also helps in defining the overall system architecture. • The system design specifications serve as an input for the next phase of the model.

43. Implementation and Unit Testing • On receiving system design documents, the work is divided in modules/units and actual coding is started. • The system is first developed in small programs called units, which are integrated in the next phase. • Each unit is developed and tested for its functionality; this is referred to as unit testing. Unit testing mainly verifies if the modules/units meet their specifications. • Integration and System Testing • These units are integrated into a complete system during integration phase and tested to check if all modules/units coordinate with each other, and the system as a whole behaves as per the specifications. • After successfully testing the software, it is delivered to the customer. • Operations & Maintenance • This phase of the model is virtually a never-ending phase. Actions taken to solve the problems or errors arises after the system become operational.

44. Spiral Model • The spiral model, also known as the spiral lifecycle model, combines the features of the prototyping model and the waterfall model. • The spiral model is intended for large, expensive, and complicated projects.

45. Steps of Spiral Model • The new system requirements are defined in as much detail as possible. This usually involves interviewing a number of users representing all the external or internal users and other aspects of the existing system. • A preliminary design is created for the new system. • A first prototype of the new system is constructed from the preliminary design. This is usually a scaled-down system, and represents an approximation of the characteristics of the final product. • A second prototype is evolved by a fourfold procedure: (1) evaluating the first prototype in terms of its strengths, weaknesses, and risks; (2) defining the requirements of the second prototype; (3) planning and designing the second prototype; (4) constructing and testing the second prototype. • The cycle keep on repeating itself untill the customer is satisfied. • The final system is constructed, based on the refined prototype.

46. Iterative Model • Iteration means the act of repeating a process with the aim of approaching a desired goal,target or result. • An iterative lifecycle model does not attempt to start with a full specification of requirements. • Instead, development begins by specifying and implementing just part of the software, which can then be reviewed in order to identify further requirements. • This process is then repeated, producing a new version of the software for each cycle of the model.

47. Prototype • A prototype is a working model that is functionally equivalent to a component of the product. In many instances the client only has a general view of what is expected from the software product. • In such a scenario where there is an absence of detailed information regarding the input to the system, the processing needs and the output requirements, the prototyping model may be employed. • This model reflects an attempt to increase the flexibility of the development process by allowing the client to interact and experiment with a working representation of the product. • The developmental process only continues once the client is satisfied with the functioning of the prototype. • At that stage the developer determines the specifications of the client’s real needs.

48. Software Prototyping • Software prototyping, a possible activity during software development, is the creation of prototypes, i.e., incomplete versions of the software program being developed. • A prototype typically implements only a small subset of the features of the eventual program, and the implementation may be completely different from that of the eventual product. • The purpose of a prototype is to allow users of the software to evaluate proposals for the design of the eventual product by actually trying them out, rather than having to interpret and evaluate the design based on descriptions.

49. Data Flow Daigram • A data-flow diagram (DFD) is a graphical representation of the "flow" of data through an information system. • Entities: can be people, departments, other companies, other systems are called sources if they are external to the system and provide data to the system, and sinks if they are external to the system and receive information from the system • Processes must have at least one input and at least one output at the primitive. • Data stores: can be online or “hard copy” (see notes on logical VS physical DFD’s below) are labeled with a noun (e.g. the label “customer” indicates that information about customers is kept in that data store)data is stored whenever there are more than one process that needs it and these processes don’t always run one after the other (if the data is ever needed in the future it must be stored) • Data flows :must originate from and/or lead to a process and data stores cannot communicate with anything except processes