SSAD

What is Process Modeling?

The act of creating a graphical representation of how a business system works.

What is the main difference between a logical and a physical DFD?

A logical DFD focuses on what the system does (the business processes), while a physical DFD focuses on how the system is implemented (the specific technology, people, and locations).

What are the four core elements of a DFD?

Entity, Process, Data Store, and Data Flow.

How should a Process element be labeled?

With a verb phrase (e.g., 'Calculate Total').

How should a Data Store or Entity be labeled?

With a noun or noun phrase (e.g., 'D1 Orders' or 'Customer').

What is the most important rule when choosing a DFD notation like Gane & Sarson or Yourdon & DeMarco?

Consistency. You must pick one notation and use it for the entire set of diagrams.

What is the rule of 'balancing' in DFDs?

The inputs and outputs of a high-level process must exactly match the total inputs and outputs of its lower-level, decomposed diagram.

Why is a direct data flow from an Entity to a Data Store illegal?

It is illegal because all data must pass through a Process to be transformed or acted upon.

What is a 'black hole' process?

A process that has inputs but no outputs.

What is a 'miracle' process?

A process that has outputs but no inputs.

What must a process do to the data it receives?

It must transform the data; the outputs should be different from the inputs.

How does a DFD show a read-and-update operation on a data store?

By using two separate arrows: one from the store (read) and one to the store (update).

What is the key difference between a DFD and a flowchart?

A DFD shows the flow of data, whereas a flowchart shows the sequence of operations or logical decisions.

What is the goal of decomposition?

To break down complex processes into finer and finer detail until each process represents a single, simple task.

Name one reason to stop decomposing a process.

It represents a single, simple task; it corresponds to a single business form or computer screen; or the system user is satisfied with the level of detail.

What are the four types of DFDs used in the typical progression of system analysis?

Current Physical, Current Logical, New Logical, and New Physical.

What is a syntax error in a DFD? Provide an example.

It is a "grammatical" error that violates the drawing rules. Examples include a "black hole," an illegal connection (e.g., store-to-store), or an unlabeled element.

What is a semantic error in a DFD?

An error in the meaning or accuracy of the diagram. The DFD follows the rules but does not correctly represent the actual business process.

What is the best way to find semantic errors?

By conducting user walk-throughs, where users validate that the DFD accurately reflects how they do their work.

What is the primary goal of the analysis phase?

To understand and document what the new system should do, resulting in a System Proposal.

List the three levels of requirements from highest-level to most detailed.

1. Business Requirements, 2. User/Stakeholder Requirements, 3. System Requirements.

Explain the difference between functional and non-functional requirements.

Functional requirements specify what the system must do (e.g., allow a user to check order history). Non-functional requirements describe qualities of the system, such as performance or security (e.g., the system must be available 24/7).

What does JAD stand for, and what is a major benefit of using this technique?

JAD stands for Joint Application Development. Its major benefit is building consensus among stakeholders and reducing scope creep by resolving issues in a collaborative session.

When is it most appropriate to use a questionnaire for requirements gathering?

When information needs to be gathered from a large and/or geographically dispersed group of people.

How does Root Cause Analysis differ from Problem Analysis?

Problem Analysis focuses on identifying problems and solutions, often leading to minor improvements. Root Cause Analysis focuses on finding the underlying source of a problem, not just its symptoms.

What is a use case, and what type of requirement is it best at describing?

A use case describes the interaction between a user (actor) and the system to accomplish a goal. It is best at describing functional requirements.

In a use case, what is the "Normal Course" (or "Happy Path")?

It is the step-by-step description of a successful interaction when everything goes as expected, without any errors or alternative paths.

Name two of the five main requirements elicitation techniques mentioned.

Any two of the following: Interviews, JAD, Questionnaires, Document Analysis, Observation.

What is the key difference between an "Alternative Course" and an "Exception" in a use case?

An "Alternative Course" describes a less common but still successful path to completing the goal. An "Exception" describes what happens when an error occurs that prevents the use case from completing successfully.