In Oracle SQL*Plus, what is AFIEDT.BUF and how is it used when editing and re running SQL statements?

Introduction / Context:
This question focuses on a classic SQL*Plus feature, the use of the AFIEDT.BUF file. When working in SQL*Plus, users can edit the current command using an external text editor. Understanding how SQL*Plus stores and retrieves the text being edited provides insight into AFIEDT.BUF and the general workings of the SQL*Plus command buffer.

Given Data / Assumptions:

- We are using SQL*Plus as the Oracle command line client.
- The EDIT command in SQL*Plus launches an external editor such as Notepad or vi.
- AFIEDT.BUF is mentioned in many Oracle training materials in this context.

Concept / Approach:
In SQL*Plus, there is an internal command buffer that stores the most recent SQL statement or PL or SQL block. When you type EDIT, SQL*Plus writes the contents of this buffer to a temporary text file named AFIEDT.BUF in the current working directory and then opens that file in the external editor. When you save and exit the editor, SQL*Plus can re load the edited text from AFIEDT.BUF back into the command buffer. You can then run the modified statement with the RUN or slash commands.

Step-by-Step Solution:
Step 1: Recall that AFIEDT.BUF is associated with the EDIT command in SQL*Plus and is not an Oracle data file. Step 2: Understand that it is created and overwritten as needed and contains only the most recent text that you edited. Step 3: Consider option A, which states that AFIEDT.BUF is the default temporary text file for the command buffer when invoking the external editor. This aligns with SQL*Plus behavior. Step 4: Option B suggests it is the main data file for tables, which is incorrect because data files have different extensions and roles. Step 5: Option C calls it a redo log file, but redo logs have specific naming conventions and are not used for editing statements. Step 6: Option D confuses it with parameter files like init.ora or spfile, which are used to start the instance.

Verification / Alternative check:
To verify, you can launch SQL*Plus, enter a query, and type EDIT. After editing and saving, you can check the current directory and inspect the AFIEDT.BUF file with a text editor. You will see that it contains the SQL statement you just edited. Deleting this file does not affect the database, only the ability to recall the last edited command buffer.

Why Other Options Are Wrong:
Option B is wrong because Oracle data files are managed by the database engine and not used as temporary text buffers. Option C is incorrect because redo log files contain binary redo information, not plain text SQL commands. Option D is mistaken because parameter files are configuration files, not buffers for SQL*Plus commands. These functions are all separate from the role of AFIEDT.BUF.

Common Pitfalls:
A common pitfall is to think that AFIEDT.BUF must be kept or backed up, when in practice it is a temporary convenience file. Another mistake is assuming that AFIEDT.BUF stores a history of commands; in fact, it usually contains only the most recently edited script. Understanding this helps avoid confusion when editing and re running SQL in SQL*Plus.

Final Answer:
AFIEDT.BUF is the default temporary text file that SQL*Plus uses to store the current command buffer when you invoke the external editor with the EDIT command.