MINGGU Ke 11 Analisa dan Perancangan Sistem Informasi · Mata Kuliah ..... Minggu …… Page 1...
-
Upload
doankhuong -
Category
Documents
-
view
219 -
download
0
Transcript of MINGGU Ke 11 Analisa dan Perancangan Sistem Informasi · Mata Kuliah ..... Minggu …… Page 1...
Mata Kuliah ............... Minggu …… Page 1
MINGGU Ke 11
Analisa dan Perancangan Sistem Informasi
Pokok Bahasan:Finalizing Design Specifications
Tujuan Instruksional Khusus:Discuss the need for system design specifications
Referensi:
(1) Hoffer, J.A., Joey F. George, dan Joseph S. Valacich
(2005), Modern Systems Analysis and Design, Edisi ke-4,
Prentice Hall. (2) Kendall, Kenneth.E. dan Julie E. Kendall
(2005), Systems Analysis and Design, Edisi ke-6, Prentice
Hall.
Mata Kuliah ............... Minggu …… Page 2
Learning ObjectivesDiscuss the need for system design specifications
Define quality requirements and write quality requirements statements
Read and understand a structure chart
Distinguish between evolutionary and throwaway prototyping
Explain the role of CASE tools in capturing design specifications
Demonstrate how design specifications can be declared for Web-based applications
15.2
Mata Kuliah ............... Minggu …… Page 3
Introduction
• Need for systems to be developed more quickly
today
• The lines between analysis and design and design
and implementation are blurring
– Traditional approaches allowed for a break between
design and implementation
– Other approaches, such as CASE and prototyping, have
caused overlap between the two phases
15.3
Mata Kuliah ............... Minggu …… Page 4
The Process of Finalizing Design
Specifications• Less costly to correct and detect errors during the
design phase
• Two sets of guidelines
– Writing quality specification statements
– The quality of the specifications themselves
• Quality requirement statements
– Correct
– Feasible
– Necessary
– Prioritized
– Unambiguous
– Verifiable15.4
Mata Kuliah ............... Minggu …… Page 5
The Process of Finalizing Design
Specifications
• Quality requirements
– Completely described
– Do not conflict with other requirements
– Easily changed without adversely affecting
other requirements
– Traceable back to origin
15.5
Mata Kuliah ............... Minggu …… Page 6
The Process of Finalizing Design
Specifications
• Deliverables and Outcome
– Set of physical design specifications
• Contains detailed specifications for each part of the
system
15.6
Mata Kuliah ............... Minggu …… Page 7
Representing Design
Specifications
• Traditional Methods
– Pre-CASE
– Documents written natural language and augmented
with graphical models
– Specification documents
• Figure 15-2 shows an example
• Several methods for streamlining
– Computer-based requirements tools
– Prototyping
– Visual development environments
15.7
Mata Kuliah ............... Minggu …… Page 8
Representing Design
Specifications• Structure Charts
– Shows how an information system is organized
in hierarchical models
– Shows how parts of a system are related to one
another
– Shows breakdown of a system into programs
and internal structures of programs written in
third and fourth generation languages
15.8
Mata Kuliah ............... Minggu …… Page 9
Representing Design
Specifications• Structure Charts
– Module
• A self-contained component of a system, defined by a function
• One single coordinating module at the root of structure chart
• Single point of entry and exit
• Communicate with each other by passing parameters
– Data couple
» A diagrammatic representation of the data exchanged between two modules in a structure chart
– Flag
» A diagrammatic representation of a message passed between two modules
15.9
Mata Kuliah ............... Minggu …… Page 10
Representing Design
Specifications• Structure Charts
– Module
• Special Symbols
– Diamond
» Only one subordinate will be called
– Curved Line
» Subordinates are called repeatedly until terminating condition is met
– Predefined modules
– Hat
» Subordinate module is important logically but code is contained in superior module
15.10
Mata Kuliah ............... Minggu …… Page 11
Representing Design
Specifications
• Structure Charts
– Pseudocode
• Method used for representing the instructions inside a module
• Language similar to computer programming code
• Two functions
– Helps analyst think in a structured way about the task a module is designed to perform
– Acts as a communication tool between analyst and programmer
15.11
Mata Kuliah ............... Minggu …… Page 12
Representing Design
Specifications
• Prototyping
– Construction of the model of a system
– Allows developers and users to
• Test aspects of the overall design
• Check for functionality and usability
– Iterative process
– Two types
• Evolutionary Prototyping
• Throwaway Prototyping
15.12
Mata Kuliah ............... Minggu …… Page 13
Representing Design
Specifications
• Prototyping
– Evolutionary Prototyping
• Begin by modeling parts of the target system
• If successful, evolve rest of the system from the
prototype
• Prototype becomes actual production system
• Often, difficult parts of the system are prototyped
first
• Exception handling must be added to prototype
15.13
Mata Kuliah ............... Minggu …… Page 14
Representing Design
Specifications
• Prototyping
– Throwaway Prototyping
• Prototype is not preserved
• Developed quickly to demonstrate unclear aspect of
system design
• Fast, easy to use development environment aids this
approach
15.14
Mata Kuliah ............... Minggu …… Page 15
Representing Design
Specifications
• Prototyping
– Oracle Designer: An Example
• Transforming and Generating the Database
– Entity-Relationship Diagramming Tool
– Database Design Transformer Tool
– Server Model Diagram
– End Result
» Generation of Data Definition Language (DDL)
scripts
– Create database by running scripts
15.15
Mata Kuliah ............... Minggu …… Page 16
Representing Design
Specifications
• Prototyping
– Oracle Designer: An Example
• Transforming and Generating Software Modules
– Data Flow Diagram
– Functional Hierarchy Diagram
– Application Design Transformer
» Transforms diagrams into software modules which
can be used to generate forms or reports
– Generate form or report in Design Editor
15.16
Mata Kuliah ............... Minggu …… Page 17
Radical Methods: eXtreme Programming
• Short cycles
• Incremental planning approach
• Automated tests
• Utilizes two-person programming team
• Planning, analysis, design and construction are
fused together into one phase
• Requirements and specifications are uniquely
captured
15.17
Mata Kuliah ............... Minggu …… Page 18
Radical Methods: eXtreme Programming
• Planning game
– Players
• Business
• Development
– Story cards
• Description of procedure or system feature
15.18
Mata Kuliah ............... Minggu …… Page 19
Radical Methods: eXtreme Programming
• Planning game
– Three phases
• Exploration
– Business creates a story card
– Development responds with time estimate
• Commitment
– Business sorts story cards into three stacks
– Development sorts story cards according to risk
– Business selects cards to include in next release of product
• Steering
– Business monitors development activity
15.19
Mata Kuliah ............... Minggu …… Page 20
Radical Methods: eXtreme Programming
• Iteration Planning Game
– Played by programmers
– Task Cards
• Several task cards generated for each story card
• Three phases
– Exploration
» Story cards converted to task cards
– Commitment
» Programmers accept responsibility for tasks
– Steering
» Programmers write code, test it and integrate it
• Game takes place during time between intervals of planning game steering phase meetings
15.20
Mata Kuliah ............... Minggu …… Page 21
Radical Methods: RAD
• Four life-cycle phases
– Planning
– Design
– Construction
– Cutover
• Iteration between design and construction
15.21
Mata Kuliah ............... Minggu …… Page 22
Electronic Commerce Application
• Microsoft FrontPage used to build
throwaway prototype
• Template based HTML
15.22
Mata Kuliah ............... Minggu …… Page 23
Summary
• Types of Design Specifications
– Written document augmented by various
diagrams
– Structure chart
– Computer-based requirements management tool
– Prototypes
• Throwaway versus Evolutionary
15.23
Mata Kuliah ............... Minggu …… Page 24
Summary
• Radical Methods
– eXtreme Programming
– RAD
• Electronic Commerce Application
– Throwaway prototyping
15.24