Data and Process Modeling and Object Modeling

Overview

With requirements defined, a system analyst focuses on how system data is transformed into useful information. The deliverable of data and process modeling is a logical model. A logical model shows what the system must do, regardless of how it will be implemented physically. Later, in the systems design phase, a physical model is built that describes how the system will be constructed. Data and process modeling involves three main tools:

• data flow diagrams
• a data dictionary
• process descriptions

In contrast, object-oriented (O-O) analysis describes an information system by identifying things called objects. An object represents a real person, a place, an event, or a transaction. For example, when a patient makes an appointment to see a doctor, the patient is an object, the doctor is an object, and the appointment itself is an object.

Object-oriented analysis is a popular approach that sees a system from the viewpoint of the objects themselves as they function and interact. The end product of O-O analysis is an object model, which represents the information system in terms of objects and O-O concepts. Object-oriented analysis provides us with another way to view and model system requirements.

Objectives

At the end of this week, you will be able to:

• Describe the relationship between logical and physical models.
• Explain data flow diagrams.
• Draw the four basic data flow diagram symbols.
• Explain the six guidelines used when drawing data flow diagrams.
• Draw context diagrams.
• Draw diagram 0 data flow diagrams.
• Draw lower-level data flow diagrams.
• Explain how to level and balance data flow diagrams.
• Create a data dictionary.
• Apply process description tools in modular design.
• Demonstrate how object-oriented analysis can be used to describe an information system.
• Explain what an object represents in an information system.
• Explain object attributes.
• Explain object methods.
• Explain object messages.
• Explain classes.
• Explain relationships among objects and classes.
• Draw an object relationship diagram.
• Demonstrate use of the UML to describe object-oriented systems, including use cases, use case diagrams, class diagrams, sequence diagrams, state transition diagrams, activity diagrams, and business process models.
• Explain how tools can support object modeling.

Learning Activities

1. Read Module 5: Data and Process Modeling.
2. Work through Module 5 Appliance Warehouse Case.
3. Read Module 6: Object Modeling.
4. Work through Module 6 Appliance Warehouse Case.

Assignments

1. Submit Module 5: Appliance Warehouse Case.
2. Submit Module 6: Appliance Warehouse Case.
3. Take the Module 5 Quiz.
4. Take the Module 6 Quiz.
5. Complete System Requirements Document - Project #1.