Lab 10
Lab 10
Lab 10
Objective:
Deeper understanding of System modeling:
Data model: entity-relationship diagram (ERD).
Functional model: data flow diagram (DFD).
Lab Tasks:
You are required to provide the following:
Data model: entity-relationship diagram (ERD) of your assigned project.
Functional model: data flow diagram (DFD) of your assigned project.
Outcomes
After this lab you will be able to produce data model and the functional model of any
software system
System Modeling
2. Background
Modeling consists of building an abstraction of reality. These abstractions are
simplifications because they ignore irrelevant details and they only represent the relevant
details (what is relevant or irrelevant depends on the purpose of the model).
A wide variety of models have been in use within various engineering disciplines for a long
time. In software engineering a number of modeling methods are also available.
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CSE304 OOSE Lab Manual
2.3.1 Entity Relationship Diagram
An entity relationship diagram (ERD) is one means of representing the objects and their
relationships in the data model for a software product.
Entity
Relationship
External entity
Process
Data flow
Control flow
Data store
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CSE304 OOSE Lab Manual
To create a DFD you need to:
Review ERD to isolate data objects and grammatical parse to determine operations.
Determine external entities (producers and consumers of data).
(one single process).
Balance the flow to maintain data flow continuity.
Develop a level 1 DFD; use a 1:5 (approx.) expansion ratio.
CASE Tools
You can use MS Visio or Visual Paradigm to create your ERD and DFD
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CSE304 OOSE Lab Manual