Chapter 6 System Analysis

These flashcards cover key concepts related to Data Flow Diagrams (DFDs) from the CSIT 317 Systems Analysis and Design lecture, providing definitions and explanations for effective study and review.

What is a Data Flow Diagram (DFD)?

A DFD visually maps the flow of information within a system or process, illustrating how data is input, processed, stored, and output.

What do the standardized symbols in a DFD represent?

They simplify complex systems and emphasize the logic of the system instead of physical implementation details.

Who popularized DFDs in the 1970s?

Larry Constantine and Ed Yourdon.

What are the four fundamental elements of DFDs?

1. Process, 2. Data Flow, 3. Data Store, 4. External Entity.

What does a Process in a DFD represent?

An activity that transforms or manipulates data and can be represented by a circle, oval, or rounded rectangle.

How is Data Flow represented in a DFD?

Data Flow is represented by an arrow labeled with the data being moved between components.

What is a Data Store?

A repository where data is held for later access, like a database or file cabinet, represented by two parallel lines or an open-ended rectangle.

How are External Entities depicted in a DFD?

External Entities are represented by a square or rectangle and denote sources or destinations of data outside the system boundary.

What notation types are used for DFDs?

The two main types of notation are Yourdon-Coad and Gane-Sarson.

What is Top-Down Decomposition?

A hierarchical approach to system analysis that starts with a high-level overview and breaks it down into more detailed components.

What is a Context Diagram?

It shows the entire system as a single process, depicting interactions with external entities and system boundaries, without internal processes or data stores.

What is the purpose of the Level 0 DFD?

It expands the system from one process into 2-3 major processes and maps high-level data flows between processes and entities.

What defines a Level 1 DFD?

It selects one process from Level 0 and breaks it into detailed sub-processes, showing specific data flows and data store connections.

What is a Level 2 DFD used for?

It further decomposes a Level 1 sub-process and displays operational details for implementation.

What are common errors to avoid in DFDs?

1. No process to move data flow, 2. Data store has no input or output, 3. Output has the same name as input, 4. Black hole or miracle processes.

What general tools can be used for diagramming DFDs?

Tools like Visual Paradigm, Lucidchart, draw.io, and miro are commonly used.

What are the steps to create a Data Flow Diagram?

1. Understand the basics, 2. Identify external entities, 3. Identify main processes, 4. Identify data stores, 5. List data flows, 6. Draw the Level 0, 7. Decompose into Level 1, 8. Validate with rules.

What is the purpose of the Library Book Loan System DFD?

It handles the process of book loans for members, from request to issue and tracking of inventory.

What key processes are involved in the Course Registration System DFD?

Student Login, View Courses, Submit Course Registration, Check Prerequisites & Availability, Confirm Registration, and Manage Course Offerings.