Project 1 Guide System Analysis & Design

Seminar 2 - Second Semester

1436/1437 – 2015/2016

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Presented by:

Dr. Souad Larabi Marie-Sainre GP1 head committee

Plan

• Introduction

• System Analysis & Design

• Object Oriented analysis

• Structured Analysis

• Database

• Web Development

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Introduction

• After Literature Review and Background phases

• System analysis & design phase

User & System requirements

Structured Approach

Object Oriented Approach

Design approach

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System analysis & Design

User

Requirements

and System

Specifications

Analysis

Design Conclusion

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System analysis & Design

• User Requirements Definition: The UR stage is considered as the ‘concept' or

‘problem definition‘ stage; UR frequently derive directly from a spontaneous

idea or thought UR should be gathered based on the user needs; UR should be clarified through criticism and

experience of existing software and prototypes; UR should be approved through interviews and

surveys; UR should be realistic (clear, verifiable, complete,

accurate, feasible).

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• System Requirement Specification A detailed statement of the results that a system is

requested to reach. A good specification gives a complete statement of what the system is to do,

A system requirements specification is normally produced in response to a user requirements.

System analysis & Design

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• Object Oriented Analysis (still growing): • Population of interacting objects of a system

• Structured Analysis (still in use today): • The traditional data or functional views

System analysis & Design

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System analysis & Design

Structured Approach

1- Use Case diagram

2- Context level DFD

3- Level-0 DFD

4- Subsequent levels DFDs (max 3 levels)

5- ER Diagram (if needed)

6- DB Shema & Dictionary (Data Design) if needed

7- Architectural Design

8- Structured English/ Decsion Tables/ Decision trees/ Flowcharts (for major processes only) – (Component Design)

9- Interface design

Object Oriented Approach

1- Use Case diagram

2- Use Cases Descriptions

3- Conceptual Diagram

4-Sequence Diagram

5- Class Diagram

6- ER Diagram (if needed) -

7- DB Shema & Dictionary (Data Design) if needed

7- Architectural Design

8- Pseudo code/ Algorithms/ Flowcharts (component Design)

9- Interface design 11/18/2015 8

Object Oriented Analysis

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Use Case Diagram

It describes the main system functions from the standpoint of an external observer.

Used during requirements elicitation to represent external behavior.

It emphasize on what the system does rather than how it.

It is created during the early stages of a project – during the analysis phase rather than during the design phase.

It provides a high-level view of what the system does and who uses it.

It provides the basis for determining the user interfaces (UIs) to the system

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Example Use cases diagram

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Example

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Example

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Conceptual (Domain) Model

A domain model illustrates meaningful concepts in a problem domain.

It’s a representation of real-world things, not software components.

It’s a set of static structure diagrams; no operations are defined.

It may show:

Concepts

Attributes of concepts.

Associations between concepts

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Domain Model

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Sequence diagrams: An Interaction Model

• An Interaction Model

• Sequence diagrams are part of the UML and are used to model the

interactions between the actors and the objects within a system.

• The objects and actors involved are listed along the top of the

diagram, with a dotted line drawn vertically from these.

• Interactions between objects are indicated by annotated arrows.

• Detail how operations are carried out

• Dynamic Diagrams

• Organized according to time • The time progresses as you go down the page

• The objects involved in the operation are listed from left to right

according to when they take part in the message sequence.

• Create a sequence diagram for each scenario

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Sequence Diagrams

:Register :ProductCatalogue Sale

addLineItem(itemID, quantity)

1. Spec=getSpecification(itemID)

2. makeLineItem(spec,quantity)

:SalesLineItem

:ProductSpec

1.1 Spec=Find(itemID)

2.1 sli= Create(spec,quantity)

2.2 Add(sli)

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Class Diagram

A class diagram shows the existence of classes and their relationships in the logical

view of a system.

UML modeling elements in class diagrams:

Classes and their structure and behavior.

Association, aggregation, dependency, and inheritance relationships.

Multiplicity and navigation indicators.

Role names.

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Class Diagram

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Structured Analysis

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System Analysis

• Basic principle: problem partition

• Partition with regard to what

– Object - Object Oriented analysis

– Function - Structural analysis

• Data Flow Modeling (DFD)

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Data Flow Modeling

• Widely used; focuses on functions performed in the system

• Uses data flow diagrams (DFDs) and functional decomposition in modeling

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Steps in Building DFDs

1. Build the context diagram

2. Create DFD fragments for each scenario

3. Organize DFD fragments into level 0

4. Decompose level 0 DFDs as needed

5. Validate DFDs with user

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Subsequent DFD levels

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Context Diagram

• Shows the overall business process as just one process

• Shows all the outside entities that receive information from or contribute information to the system

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Level 0 Diagram

• Shows all the processes that comprise the overall system

• Shows how information moves from and to each process

• Adds data stores

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Level 0 Diagram

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Level 1 Diagrams

• Shows all the processes that comprise a single process on the level 0 diagram

• Shows how information moves from and to each of these processes

• Level 1 diagrams may not be needed for all level 0 processes

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Level 2 Diagrams

• Shows all processes that comprise a single process on the level 1 diagram

• Level 2 diagrams may not be needed for all level 1 processes

• Correctly numbering each process helps the user understand where the process fits into the overall system

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Composite & Elementary Flows

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DFD – Common Errors

Miracle

Black Hole

Gray Hole

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Illegal Data Flows

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DFD drawing – common errors

• Unlabeled data flows

• Missing data flows

• Extraneous data flows

• Consistency not maintained during refinement

• Missing processes

• Too detailed or too abstract

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Logic Modeling

• Data flow diagrams do not show the logic inside the processes.

• Logic modeling involves representing internal structure and functionality of processes:

– Structured English

– Decision Tables

– Decision Trees

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Logic Modeling

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Logic Modeling

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Logic Modeling

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Database

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Weak Entity

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DB SCHEMA

How to derive a set of relations from a conceptual data model.

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Student (Student_ID, Name, DOB)

Student_Phone ( Student_ID, Phone)

Enroll (Student_ID, Code, Grade)

Course (Code, Name, Instructor_ID)

Instructor (Instructor_ID, Name, city, street) 11/18/2015 42

Section (Section#, Code, Enrollment_limit)

Course (Code, Name) 11/18/2015 43

DB DICTIONARY

Entity dictionary

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Entity Name Description Aliases Occurrence

Student General term describing all enrolled students.

Students can enroll in several courses.

Course A general term describing all courses offered by the university.

Each course is taught by one teacher.

Instructor The person who teaches courses at the university.

Teacher The instructor can teach many courses. 11/18/2015 45

DB DICTIONARY

Relationships dictionary

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Entity Name Multiplicity Relationship Entity Name Multiplicity

Student 0..* Enroll Course 0..*

Course 0..* Teaches Instructor 1..1

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DB DICTIONARY

Attributes dictionary

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Entity name

Attribute Description Data Type

Length Nulls

Multi-valued

Default Value

Range PK CK

Inst

ruct

or

Instructor_ID

Uniquely identifies instructor.

varchar 5 no no Y Y

Name Name of instructor

varchar 30 no no

Address

City The city where the instructor lives.

varchar 10 no no

Street The street where the instructor lives.

varchar 20 no no

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Web Development

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How to Choose a Programming Language

• Figure out what works for the team.

• Find out what works in context.

• Consider ease of learning.

• Evaluate the availability of tools for the potential computer programming languages.

• Look at cross-platform ability.

• Determine the ease of server-side and client-side scripting.

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Popular Web Programming Language

Server-side:

• PHP with MySQL

• ASP.NET with SQL Server Express

• Python with MySQL

• Java Servlets with JDBC (support different DBs)

– Java Hosting Servers are different from Regular web Hosting.

• You should check that the hosting server support Java

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Responsive Web Design

• Responsive web design (RWD) is an approach to web design aimed at crafting sites to provide an optimal viewing experience.

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Responsive Web Design

• How to achieve? • Use responsive templates

• Use framework (e.g. Bootstrap and Foundation)

• Built it: – Media queries

– Fluid Grids

– Fluid Media

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References

• Guide to the User Requirements Definition phase, ESA PSS-05-02 Issue 1 Revision 1 March 1995

• Modern Systems Analysis and Design by Jeffrey A. Hoffer, Joey George, Joe A. Valacich

• http://en.wikipedia.org/wiki/Responsive_web_design

• http://learn.shayhowe.com/advanced-html-css/responsive-web-design/

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