Structured analysis
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Structured Analysis. Component of Structure Analysis. Graphic symbols. Data dictionary. Procedure and process description. Rules. Data Flow Analysis. Data drive business activity. They can trigger events.

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Structured Analysis

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Structured analysis

Structured Analysis


Component of structure analysis

Component of Structure Analysis

  • Graphic symbols.

  • Data dictionary.

  • Procedure and process description.

  • Rules.


Data flow analysis

Data Flow Analysis

  • Data drive business activity. They can trigger events.

  • Following the flow of data through the business process tells a great deals about how the organizational objective are accomplish.

  • It documents the finding in data flow diagram.


Tools for data flow strategy

Tools for data flow strategy

  • Data flow strategy shows the use of data in the system pictorially.

  • Data flow tools helps in understanding business process by illustrating essential component of the system and their interconnection.


Tools for data flow strategy1

Tools for data flow strategy

  • Data flow analysis make use of the following tools:

  • Data flow Diagram (DFD).

  • Data Dictionary.

  • Data structure diagram.

  • Structure chart.


Dfd s notation

DFD's Notation


Data flows

Data flows

  • Data flows represent the data being passed into or out of a process, source, sink or store. It is represented as a labeled arrow:

Taxable Income


Process

process

  • process are denoted by circles with one or more incoming and outgoing information flows:

Taxable Income

Tax owed

Calculate

Tax

Tax Tables


External entities

External Entities

  • Entities (Information sources and sinks) are information that come into the system, or leave the system, and are represented by squares:

Pay

Hours

Payroll System

Pay Check

Rate


Information stores

Information stores

  • Information Stores represent locations where information can be store for the duration of the system activity:

Total Payroll Expense


Types of dfd

Types of DFD

  • Physical DFD: It shows what task are carried out and how they are performed.

  • Logical DFD: Focus on the flow of data between process without regards for the specific device, storage location, people etc.


Structured analysis

Data Flow Diagrams Levels

DeMarco & Yourdon

Context Level DFD

Source/ Sink

Source/ Sink

0.0

Process

Source/ Sink

Data Flow

Data Flow

Data Flow

Level 0 DFD

0.0

Process

1.0

Process

Data Flow

Data Flow

Data Flow

Source/ Sink

2.0

Process

Source/ Sink

DATA STORE

Data Flow

Data Flow

Data Flow

Data Flow Lines

3.0

Process

Data Flow


Structured analysis

Data Flow Diagrams Levels

Source

Source

Sink

DeMarco & Yourdon

Level 1 DFD (and on)

Source/ Sink

Data Flow

1.1

Process

DATA STORE

0.0

Process

1.2

Process

Data Flow

DATA STORE

Data Flow

Data Flow Lines


Structured analysis

Data Flow Diagrams Levels


Structured analysis

Creating Data Flow Diagrams

Steps:

  • Create a list of activities

  • Construct Context Level DFD(identifies sources and sink)

  • Construct Level 0 DFD (identifies manageable sub process )

  • Construct Level 1- n DFD (identifies actual data flows and data stores )


Structured analysis

Creating Data Flow Diagrams

Lemonade Stand Example


Structured analysis

Creating Data Flow Diagrams

Example

Steps:

The operations of a simple lemonade stand will be used to demonstrate the creation of dataflow diagrams.

  • Create a list of activities

  • Construct Context Level DFD(identifies sources and sink)

  • Construct Level 0 DFD (identifies manageable sub processes )

  • Construct Level 1- n DFD (identifies actual data flows and data stores )


Structured analysis

Creating Data Flow Diagrams

Example

  • Create a list of activities

Think through the activities that take place at a lemonade stand.

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product


Structured analysis

Creating Data Flow Diagrams

Example

  • Create a list of activities

Also think of the additional activities needed to support the basic activities.

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor


Structured analysis

Creating Data Flow Diagrams

Example

  • Create a list of activities

Group these activities in some logical fashion, possibly functional areas.

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor


Structured analysis

Creating Data Flow Diagrams

Example

  • Construct Context Level DFD(identifies sources and sink)

Create a context level diagram identifying the sources and sinks (users).

Context Level DFD

Sales Forecast

CUSTOMER

0.0

Lemonade System

EMPLOYEE

Order

Production Schedule

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor

Product Served

Pay

Payment

Time Worked

Received Goods

Payment

Purchase Order

VENDOR


Structured analysis

Creating Data Flow Diagrams

Example

  • Construct Level 0 DFD (identifies manageable sub processes )

Create a level 0 diagram identifying the logical subsystems that may exist.

Level 0 DFD

1.0

Sale

Sales Forecast

Customer Order

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor

Product Ordered

Payment

CUSTOMER

2.0

Production

EMPLOYEE

Production Schedule

Product Served

Inventory

Received Goods

VENDOR

3.0

Procure-ment

Purchase Order

Order Decisions

Payment

Pay

Time Worked

4.0

Payroll


Structured analysis

Creating Data Flow Diagrams

Example

  • Construct Level 1- n DFD (identifies actual data flows and data stores )

Create a level 1 decomposing the processes in level 0 and identifying data stores.

Level 1 DFD

CUSTOMER

Customer Order

Request for Forecast

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor

ORDER

1.1

Record Order

1.3

Produce Sales Forecast

Severed Order

Payment

Sales Forecast

1.2

Receive Payment

PAYMENT


Structured analysis

Creating Data Flow Diagrams

Example

  • Construct Level 1 (continued)

Create a level 1 decomposing the processes in level 0 and identifying data stores.

Level 1 DFD

Product Order

ORDER

2.1

Serve Product

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor

Quantity Severed

RAW MATERIALS

Production Schedule

2.2

Produce Product

Quantity Used

INVENTORTY

Production Data

2.3

Store

Product

Quantity Produced & Location Stored


Structured analysis

Creating Data Flow Diagrams

Example

  • Construct Level 1 (continued)

Create a level 1 decomposing the processes in level 0 and identifying data stores.

Level 1 DFD

Order Decision

PURCHASE ORDER

3.1

Produce Purchase Order

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor

Quantity On-Hand

RAW MATERIALS

Quantity Received

Received Goods

3.2

Receive Items

RECEIVED ITEMS

Payment Approval

3.3

Pay Vendor

VENDOR

Payment


Structured analysis

Creating Data Flow Diagrams

Example

  • Construct Level 1 (continued)

Create a level 1 decomposing the processes in level 0 and identifying data stores.

Level 1 DFD

Time Worked

TIME CARDS

4.1

Record Time Worked

Customer Order

Serve Product

Collect Payment

Produce Product

Store Product

Order Raw Materials

Pay for Raw Materials

Pay for Labor

Employee ID

EMPLOYEE

Payroll Request

4.2

Calculate Payroll

Unpaid time cards

PAYROLL

Payment Approval

4.3

Pay Employee

PAYMENTS

Payment


Structured analysis

Process Decomposition

1.0

Sale

1.1

Record Order

1.2

Receive Payment

2.0

Production

2.1

Serve Product

2.2

Produce Product

2.3

Store

Product

0.0

Lemonade System

3.0

Procure-ment

3.1

Produce Purchase Order

3.2

Receive Items

3.3

Pay Vendor

4.0

Payroll

4.1

Record Time Worked

4.2

Calculate Payroll

4.3

Pay Employee

Context Level

Level 0

Level 1


Developing dfd

Developing DFD

  • The analyst must first study current system.

  • The physical system is translated into logical description focusing on data and process.

  • Data flow diagram are of two types:

  • Physical DFD: It shows what task are carried out and how they are perform.

  • Logical DFD: Focusing on flow of data between process without regards for specific device, storage location or people in the system.


Data dictionary

Data Dictionary

  • A data dictionary is a catalog, a repository of element in a system.

  • The major elements are dataflow, data store and process.


Uses of data dictionary

Uses of Data Dictionary

  • To manage the detail in large systems.

  • To communicate a common meaning for all system elements.

  • To document the feature of the system.

  • To facilitate analysis of the details in order to evaluate characteristic and determine where system changes should be made.

  • To locate errors and omissions in the system.


Contains of data dictionary

Contains of Data Dictionary

  • Data Elements: The most fundamental data level is data element.

  • Data Name.

  • Data description.

  • Aliases.

  • Length.

  • Data Value(Prefix).


Contains of data dictionary1

Contains of Data Dictionary

  • Data Structure: A data structure is a set of data item that are related to one another and that collectively describe a component in the system.

  • Sequence Relationship.

  • Selection Relationship.

  • Iteration Relationship.

  • Optional Relationship.


Notation in data dictionary

Notation in Data Dictionary

  • Symbols:

    • +and

    • []Either/or

    • {}iteration of

    • ()optional


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