The document presents an overview of system analysis and the role of a system analyst, including the skills required and the use of data flow diagrams (DFDs) for visualizing data movement in systems. It details the components, levels, guidelines for creating DFDs, along with their benefits and limitations, as well as practical applications in requirement analysis, process improvement, documentation, data modeling, quality assurance, and progress tracking. The content emphasizes the importance of a system analyst in bridging business needs with IT solutions.

1. System Analyst and
DFD
PRESENTED BY
• Ichchha Ramtel
• Janis Adhikari
• Dikshant Shrestha
• Madav Acharya
National College of Management
and Technical Science
Samakhushi, Kathmandu
PRESENTATION ON
2024/08/24

2. Table of content
• System Analyst
• Role of system Analyst
• Skills required for system analyst
• Data flow diagram
• Component of DFD
• Levels of DFD
• Guidelines for creating DFD
• Benefits of DFD
• Limitations of DFD
• Practical Applications of DFD

3. System Analyst
• System Analysis is the process of studying and understanding a
system, identifying its components, and designing solutions to
improve its efficiency.
• A System Analyst is a professional who uses analysis and design
techniques to solve business problems using information
technology.
• To bridge the gap between business needs and IT solutions.

4. Role of System analyst
• Requirement gathering
• System design
• System implementation
• System testing
• Documentation
• Trouble shooting and support

5. Skills required for a system analyst
• Technical skills
• Analytical skills
• Communication skills
• Problem skills
• Project management

6. Data Flow Diagram (DFD)
• A data flow diagram (DFD) is a graphical representation of the
movement of data between external entities, processes and data stores
within a system
• Simply put, DFD’s show how data moves through an information
system.

7. Components of DFD
• Source/Sinks (External Entity)
• Process
• Data store
• Dataflow

8. External Entity (Source/Sink)
• People or organization that sends or receive data into or from system
• It is denoted by Rectangle symbol.
• For example , Customer in a E-commerce system.
Customer

9. Process
• Represent tasks, activities, or functions where data is processed. Each
process transforms incoming data into outgoing data.
• It is represented by Circle or rounded Rectangle
• For example: Order process in E-commerce software
Order Orders
OR

10. Data Store
• Represent places where data is stored within the system.
• This could be a database, a file, or any repository.
• It is represented by open ended rectangle or two parallel line
Data store Data Store
OR

11. Data flow
• Represent the movement of data between processes, data stores, and
external entities.
• Represented by arrow
• The direction of the arrow indicates the flow of data

12. Levels of DFD
Level 0 DFD:
Represents the highest level of abstraction, showing the system as a
single process with external entities.
Level 1 DFD:
Breaks down the system into major processes and shows the
interactions between them.
Level 2 DFD:
Further decomposes the processes into sub-processes to provide more
detailed information.

13. Guidelines for creating DFD
• Process Flows: Each process must have at least one outgoing and
one ingoing data flow.
• Data Store Connectivity: Data stores should have at least one
incoming and outgoing data flow.
• Entity-Process Link: Entities must be connected to a process by a
data flow.
• Avoiding Crossings: Data flows cannot cross with each other.
• External Entity Access: Data stores cannot directly connect to
external entities.

14. Benefit of DFD
• A graphical technique that is relatively easy to understand for
stakeholders and other users.
• Provides a detailed view of the system components and
boundaries.
• Provide clear and detailed information about the processes
within a system.
• Shows the logic of the data flow.
• Presents a functional breakdown of the system.
• Used as a part of the system documentation.

15. Limitations of Data Flow Diagram
• 1. Lack of Detail:DFDs provide a broad overview of a system and its data
flows, but they do not capture the details of how data is processed within
each process. This can lead to an oversimplified understanding of the
system.
• 2. Ambiguity:DFDs can be interpreted differently by different people
because there is no strict standardization in terms of symbols and
notations. This ambiguity can cause miscommunication among
stakeholders.
• 3. Lack of Control Information:DFDs do not represent the control flow or
decision logic within the system, making it difficult to understand the
conditional paths that might exist.

16. • 4. Scalability Issues:For large systems, DFDs can become extremely
complex and hard to manage, leading to diagrams that are difficult to
understand and maintain.
• 5. Not Suitable for All Systems:DFDs are not well-suited for systems where
data flow is not the primary concern, such as systems that are more
focused on complex algorithms or user interfaces.
• 6. Maintenance Challenges:As the system evolves, keeping the DFD up to
date can be challenging. Changes in the system require the DFD to be
revised, which can be time-consuming.

17. Practical Application of DFD
• 1.Requirement Analysis: During the initial stages of system
development, DFDs are used to capture the functional requirements
of a system. They help in understanding the data inputs, processes,
and outputs of the system, providing a clear picture of the business
processes and information flow.
• 2.Process Improvement: Businesses use DFDs to model and analyze
their existing processes. By mapping out how data flows through
different business functions, organizations can identify bottlenecks,
inefficiencies, and areas for improvement.

18. • 3.Documentation: DFDs serve as part of the system documentation, providing
a visual reference that can be used throughout the software development
lifecycle. This is especially useful for maintaining and updating systems over
time.
• 4.Data Modeling: DFDs are used to identify the data needs of a system and
how data should be organized. They help in designing the structure of
databases by showing how data flows into and out of various data stores.
• 5.Quality Assurance: In quality assurance processes, DFDs are used to verify
that the system’s design aligns with the business requirements and that data
flows as expected.
• 6.Progress Tracking: DFDs help in tracking the progress of system development
by serving as a reference point for what has been completed and what is still
in progress.