A logical flow chart is a visual representation detailing the flow of data and processes. It focuses on what happens to the data, rather than how it happens physically. Based on the reference, a logical flow chart shows where data flows from and to, as illustrated by an employee looking up the price of an item.
While the reference provided discusses logical data flow diagrams (and contrasts them with physical flow diagrams), we can infer some properties of logical flowcharts more generally.
Key Characteristics of Logical Flow Charts:
- Focus on Data Flow: They emphasize the movement of data between different entities or processes.
- Abstraction of Physical Implementation: They abstract away the physical mechanisms used to accomplish the data flow. For example, instead of showing the steps involved in scanning a barcode (as in a physical flow diagram), a logical flow diagram would simply show that "product information" is retrieved.
- Emphasis on What, Not How: They describe what actions are performed, not how those actions are implemented.
- High-Level Overview: They offer a broad overview of the system's data flow and processes.
Example:
Consider a simple online shopping scenario.
| Element | Logical Flow | Physical Flow |
|---|---|---|
| Customer Action | Customer adds item to cart. | Customer clicks "Add to Cart" button which triggers a JavaScript function that updates a session variable on the server via an AJAX request. |
| System Action | System updates shopping cart information. | Server-side code receives the AJAX request, updates the user's session data with the new item, and sends a confirmation response to the browser. |
| Result | Shopping cart contents are updated and displayed to the customer. | The browser receives the confirmation response and updates the shopping cart display using JavaScript. |
In this example, a logical flow chart would show "Customer adds item to cart -> System updates shopping cart information -> Shopping cart contents are updated". A physical flow chart would delve into the specific buttons, scripts, servers, and communication protocols involved.
