Systems analysis and design /Alan Dennis, Barbara Haley Wixom, business analysis benchmark - full vitecek.info; accessed February,. 1. System Analysis and Design. Complete Introductory Tutorial for Software Engineering. Table of contents. Chapter 1: Introduction to Systems. This page is intentionally left blank SYSTEM ANALYSIS AND DESIGN Fifth Edition .. business analysis benchmark - full vitecek.info; accessed February,
|Language:||English, Spanish, Arabic|
|Genre:||Science & Research|
|PDF File Size:||18.30 MB|
|Distribution:||Free* [*Regsitration Required]|
System Analysis and Design Tutorial in PDF - Learn System Analysis and Design in simple and easy steps starting from basic to advanced concepts with. The primary objective of systems analysis and design is to improve organizational systems. This tutorial provides a basic understanding of system characteristics. Systems Analysis and Design. Michael Brydon. Summer Slide 2. Introduction to the Course. Course structure. Lectures: material from the Dennis text.
Interview Opening: Intended to influence or motivate the interviewee to participate Interview body: Obtain interviewees response to your list of questions Interview conclusion: Express your appreciation. Important for maintaining good relationship and trust. Building a small working model of the users requirements or a proposed design for an information system. Can also be used to perform fact-finding requirement analysis discovery prototyping.
Allows analyst to quickly create mock forms and tables to simulate the implemented system. May extend the development schedule Increase the development costs. Highly structured group meeting are conducted to analyze problems and define requirements. Single person in top management who makes the final decision.
Facilitator Single individual who plays the role of the leader or facilitator. Someone who has excellent communication skills. Both users and managers are relied on to ensure that their critical success factors are being addressed Scribes Those who are keeping responsible for keeping records pertaining to everything discussed in the meeting.
System analysts frequently play this role. Usually consists of members of the project team. Document Flow Diagrams Used to identify physical movement of documents. Or de r Purc has e Purch.
Supplier Dept. Document Flow Diagrams shows where the document comes from, where it goes to , and what it is called. Pu Dept. Document Flow Diagrams Used to examine the flow of documents within the existing system. Order Purch. Invoice Dept.
De liv. Supplier Purch. Document Flow Diagrams Maintenance Example: Purchasing System. It is a communication tool: Such a repository can prevent unnecessary repetitions when someone leaves the project team. Proper documentation ensures that all the information developed about the system is always available to new people joining the project.
Documentation is also a management tool: It supports management in two ways: Is also a part of the phase output. Also known as requirements statement, requirements specification, and functional specification. Requirement Definition Document Consists of Functions and services the system should provide Nonfunctional requirements systems features, characteristics, and attributes Constraints Information about other systems with which the system must interface No standard format for the document.
Requirement Definition Document Readers of the document System Owners and Users to specify their requirements and any changes that may arise. Developers to understand what is required and to develop tests to validate the system. Introduction Technique for organizing and documenting the structure and flow of data through a systems process and the logic, policies, and procedures to be implemented by a systems process.
Logical Models Physical Models Other names: Other names: Show not only what a system is or does. But also how the system is physically and technically implemented.
Implementation dependent Reflect technology choices and the limitations of those technology choices Used to Depict technical designs. Program Structure Charts Logic Flow Charts Decision Tables, are some examples for various types of process models found in early software engineering methods and programming. Gane and Sarson notation is widely popular. Represented An external agent is an by a square outside person e. Bank An External that interact with the system.
Agent Also called an external entity. An External External Agent external to the system being analyzed or designed. A Data Store is an Data store inventory of data.
That is, stored data A Data Store intended for later use Represented by data at rest. Also the open-end box known as a file or database. These include Persons: Customer, Employee Places: Building, Room, Campus Objects: Book, Machine, Product Events: Invoice, Order, Registration, Renewal Concepts: Course, Fund, Stock. The arrow head indicates Data flow name the direction of data flow.
Label the arrows with the A Data Flow name of the data that moves through it. External External A diagram that shows the Agent Agent system as a black box and its main interfaces with its environment. External Used to document the Agent Process scope of the system Also known as environmental model.
External Agent. Need to identify the data flows and the external agents needed for the context diagram. Add the data flows between each external agent and the process representing the entire system.
Order Purchasing Supplier Invoice System. Whenever an account holder wants to withdraw some cash, he presents a cheque or withdrawal slip. The account is checked for the appropriate balance. If balance exists, the cash is paid and the account is updated. Is the act of breaking a system into its component subsystems , processes and sub processes. Top level function is then decomposed to its component functions. Wit Ack hdr now awa Account ledg l eme Holder nt.
Process 1 8 No data flow should ever go unnamed. Reservation ready notice.
Document Flow Diagram Modeling method or technique used to illustrate movements of documents. What process generates this document flow? What process receives this document? Is the document stored by a process? Where is the document stored?
Is the document created from stored data? Stude i ne n e slip. S Library New member details Admin. DFDs handle transformation from physical document to logical data Advances in technology mean that electronic means are increasingly supplementing the paper based documents.
Fi ip Me p mb er c ard Library System Admin. Sl be rc Se. Fi em d. Registration Lib em me m ber y s t New S Details. Member Member Me m. Sl em Lending. Book details m. Boo k deta New member details ils Member member Mem. Registration Book Details Registration details. New member Admin. Users are not overwhelmed by the overall size of the system A powerful communication tool between users and technical professionals.
A language and syntax, based on the relative strengths of structured programming and natural English, for specifying the underlying logic of elementary processes on process models. A tabular form of representation that specifies a set of conditions and their corresponding actions Very useful for specifying complex policies and decision making rules.
There exist several notations for an ERD Martin notation is widely used. Entity Relationship Diagrams Shows data in terms of the entities and relationships described by data. Entities An entity is something about which the business needs to store data. Synonyms entity type and entity class.
Entity Instance An entity instance is a single occurrence of an entity. Every entity must have an identifier or key to uniquely identify each instance. Consider Martin notations. The named rounded rectangle represent the entity. A line represent the relationship. Sometimes called as element, property, or field.
It is Name sometimes called an identifier. Address Age. This person can be identified using his ID number. Compound Attribute is one that actually consist of other attributes. Synonyms- composite attribute, concatenated attribute Example: Data type What type of data can be stored in that attribute Number, Date, Text etc.
Domain What values an attribute can legitimately take on. Refer to table in pg Ref1. Default Is the value that will be recorded if not specified by the user. Zero, one or more I may have one, some friends or none. More than one I am working on many projects. Binary Relationship - When two different entities participates in a relationship. Synchronization is the process of maintaining consistency between the different types of models.
Object Modeling techniques prescribe the use of methodologies and diagramming notations that are completely different from the ones used for data modeling and process modeling. Attributes The data that represents characteristics of interest about an object e. Customer Attributes: Customer no, first name, last name, home address, work address, contact no,etc.
Sometimes referred to as an Object. Drawn using a rectangle with the name of the object instance The name consists of the attribute that uniquely identifies it, followed by a colon and then the name of the class in which the object has been categorized.
Customer Also known as a method, operation or service e. Door behavior: Objects encapsulates what they do. When most people watch a television show, - they usually dont know or care about the complex electronics that sit in back of the TV screen - or the operations that are happening. The TV hides its operations from the person watching it. You interact with a text book by reading it, with a telephone by using it, People interact with each other by communicating with them.
An association is unidirectional one way or bi- directional two way. Conversely, a smaller part class is part of a whole larger class. A club a club is made up of several club members A computer a computer contains a case, CPU, motherboard, power supply etc. If the whole were to die, the part would die with it. A stronger form of aggregation. The relationship between club and club member would not be composition, because members have a life out-side the club and can, belong to multiple clubs.
Each part can belong to only one whole, therefore, multiplicity needs to be specified only one for the part Components will live and die with the whole object. Close Behavior: Close Slides downwards Swings shut. Both have the common behavior But the way it has been carried Out differs from one another. Produces a design specification for the new system. Also known as physical design. Design inputs, outputs, files, databases and other computer based components.
Systems analysis - emphasize on the business problem Systems design - emphasize on the technical or implementation concerns of the system.
Process A11 Process A1 is a process-oriented. Process A technique for breaking up Process A2 Process A12 a large program into a hierarchy of modules Process A3 Process A13 Process A4 result- in a computer program that is easier to synonyms are top-down implement and maintain program design and change.
The software model derived from structured design It is derived by studying the flow of data through the program.
Modern Structured Design. Structure Chart Parameter Passing -The calling module passes a set of values to the called module and receives a set of values in return. These values are passed as parameter values. Structure Chart Execution Sequence By convention, modules are executed from left to right in each level. Module Output Total is the last module to be called.
Certain conventions are also used to represent decisions and repetition. Decisions occur whenever a calling module has to decide to call only one of a number of modules. Repetition occurs when some modules are called repetitively by the calling module.
The objective of structured design is to produce a good design. Information Engineering IE. Primary tool of information engineering is a data model diagram ERD. Involves conducting a business area requirements analysis from which information system applications are carved out and prioritized.
The prototyping approach is an iterative process involving a close working relationship between the designer and the users. Prototyping encourages and requires active end- user participation. Iteration and change are a natural consequence of systems development - that is end-users tend to change their minds.
Prototyping endorses the philosophy that end-users will not know what they want until they see it. Key Benefits: Prototypes are an active, model that end-users can see, touch, feel, and experience. An approved prototype is a working equivalent to a paper design specification, with one exception -- errors can be detected much earlier. Prototyping can increase creativity because it allows for quicker user feedback, which can lead to better solutions. Prototyping accelerates several phases of the life cycle, possibly bypassing the programmer.
Prototyping encourages ill-advised shortcuts through the life cycle. JAD sessions for systems design, systems designer - role of facilitator for possibly several full-day workshops intended to address different design issues and deliverables. RAD is the merger of various structured techniques especially the data-driven information engineering with prototyping techniques and joint application development techniques to accelerate systems development. RAD calls for the interactive use of structured and prototyping to define the users requirements and design the final system.
The newest design strategy Used to refine the object requirements definitions identified earlier during analysis and to define design-specific objects e. Process Model the technical and human decisions to be ID optional implemented as part of an information system.
A physical process is either a processor, such as a computer or person, or a technical implementation of specific work to be performed, such as a computer program or manual process. A physical DFD would model that network structure. Each logical process must be implemented as one or more physical processes as some logical processes must be split into multiple physical processes. A database command or action create, read, update, or delete Import of data from or the export of data to another information system across a network.
Flow of data between two modules within the same program. External agents were classified during systems analysis as outside the scope of the systems and therefore, not subject to change. Physical Data store MS Access: Databases are a shared resource. A database should be adaptable to future requirements and expansion.
Issues to be addressed during database design include how programs will access the data Programming data structures and their impact on performance and flexibility Internal controls to ensure proper security and disaster recovery technique, in case data is lost or destroyed. Record size and storage volume requirement. Design the System Database Purpose is to prepare technical design specification for the database.
Participants Systems analyst participate in database modeling System designers complete the database design Data administrator recognize that the new system most likely use s some portion of an existing database System builders build a prototype database for the project Inputs: The precise format and layout of the outputs must be specified. Internal controllers must be specified to ensure that the outputs are not lost, misrouted, misused, or incomplete.
Editing controllers must be designed to ensure the accuracy of input data. Design the System Interface. For dialogue design the designer must consider Terminal familiarity Possible errors and misunderstandings that the end user may have or may encounter The need for additional instructions or help at certain points The screen content and layout.
Package all the specifications from the previous design tasks into a set of specifications. Guide the computer programmers activities. The deliverable: Information Technology Architecture System analysts must continuously read popular trade journals to stay abreast of the latest technologies and techniques that will keep their customers and their information systems competitive. The information system framework provides one suitable framework for understanding IT architecture.
Today information systems are no longer monolithic, mainframe computer based systems. Components are distributed across multiple locations and computer networks Processing work load required to support these components are distributed across multiple computers on the net work. Why use distributed systems? Modern businesses are already distributed Distributed computing moves information and services closer to the customers Consolidates the incredible power More user friendly as they use the PC as the user interface processor PCs and network servers are much less expensive than mainframes Thus, there is a big trend towards distributed systems.
Distributed Systems. Disadvantages Network data traffic can cause congestion that actually slows performance. Higher security risk due to more possible access points for intruders and possible communication with insecure systems. File server Architecture A LAN Local area network based solution LAN is a set of client computers connected over a relatively short distance to one or more servers A server computer hosts only the data layer All other layers are implemented on the client PC.
Disadvantages Large amount of unnecessary data must be moved between the client and the server Reduce network and application performance The client PC must be robust. Client Server Architecture The presentation, presentation logic, application logic, data manipulation and data layers are distributed between client PCs and one or more servers. Client Computers: A personal that does a personal computer, not have to be very notebook computer, or powerful acts as a work station that is terminal typically powerful e.
Remote desktop e. Database Server: A server that hosts one or more databases. Transaction Server: Application Server: A server that hosts application logic and services for an information system Messaging or Groupware Server: A server that hosts services for groupware. Web Server: Application logic is placed on its own server Presentation logic and Presentation are placed on the clients.
Stores data in a tabular form Each file is implemented as a table Each field is a column in the table Each record is a row in the table Related records between two tables e. The software required to implement distributed relational databases Controls access to and maintenance of the stored data in the relational format Provides back-ups, recovery and security Also called as client-server database management systems e.
Supports two types of data Data partitioning: Data Architectures. For a given information system application the data architecture must specify the RDBMS technology and the degree to which data will be partitioned or replicated. Batch inputs or Outputs Transactions are accumulated into batches for periodic processing Batch inputs e.
Online inputs or Outputs Provide for a more conversational dialogue between the user and the computer applications. Provide immediate feedback in response to transactions, problems, and inquiries.
Remote batch Combines the best aspects of batch and online inputs and outputs. In batch systems, keying errors can be eliminated through optical character reading OCR and optical mark reading OMR technology The real advance in keyless data entry are coming for online systems in the form of auto-identification systems.
Pen input A pen-based operating system become more widely available and used e. Imaging and Document Interchange The actual images of the forms and data are transmitted and received. Demand for Project managers in the Information system community is strong. Information system project managers come from the ranks of experienced IS developers such as systems analysts Systems Analysts should be aware of Project management processes, tools and techniques.
Project Management Project manager The person responsible for supervising a systems project from initiation to conclusion. Should possess a wide range of technical, management, leadership and communication Project skills. It is the process of Scoping Planning Staffing. Directing Organizing Controlling. Necessary to ensure that the project. PM is a cross life cycle activity because it overlaps all phases of any systems development methodology.
A project is successful if The resulting Information system is acceptable to the customer The system is delivered on time The system is delivered within budget The system development process had a minimal impact on ongoing business operations.
Causes of failed projects Over optimism The mythical man-month Inadequate people management skills Failure to adapt to business change Insufficient resources Failure to manage to the plan.
Major cause of project failure is that most project managers were not educated or trained to be project managers. Project Manager Competencies. Good project managers possess a core set of competencies. Some of these can be taught in courses, books and workshops Some come only with professional experience in the field basic premises of project management competencies: Project Manager Competencies Influence Competencies.
Project management functions Scoping: A project manager must scope project expectations and constraints in order to plan activities, estimate costs, and manage expectations.
What skills will be needed? How much will it cost? Can some of the tasks overlap? Project management functions Scheduling: Project management functions Controlling: They learn from mistakes and plan for continuous improvement of the systems development process.
All these functions depend on ongoing interpersonal communication among the project manager. The team, and other managers. Project Management Tools and Techniques. Project Management Tools and Techniques A PERT chart is a graphical network model that depicts a projects tasks and the relationships between those tasks.
Boxes represent project tasks Content of the boxes can be adjusted to show various project attributes such as schedule and actual start and finished times.
Arrow indicates that one task is dependent on the start or completion of another task. Project Management Tools and Techniques Gantt Chart The most commonly used project scheduling and progress evaluation tool a simple horizontal bar chart that depicts project tasks against a calendar. Each bar represents a named project task. The tasks are listed vertically in the left-hand column.
Project Management Tools and Techniques e. Gantt Chart. For more details: Project Management Tools and Techniques Gantt Chart Advantages Clearly show overlapping tasks Tasks that can be performed at the same time the bars can be shaded to clearly indicate percentage completion and project progress Shows which phases are ahead of and behind schedule at a glance.
Gantt Vs. Gantt charts are more effective when seeking to communicate schedule PERT charts are more effective when you want to study the relationships between tasks. We have memorized your details. All you need to do is click "download". This book introduces systems analysis and design principles and techniques which are used for building information systems.
Each phase of the systems development life cycle is concisely covered. Contents include structured analysis techniques, object modelling with the UML and Agile approaches to development.
Also covered is system design including data design, human computer interaction and system architectures, along with system implementation and maintenance.