Consider the following PL/SQL procedure designed to retrieve customer information and handle potential errors:

If get_customer_info(0) is executed, what will be the output?

Question

Consider the following PL/SQL procedure designed to retrieve customer information and handle potential errors:

If get_customer_info(0) is executed, what will be the output?

BlackTom AI · Accepted Answer

Because p_customer_id <= 0 triggers RAISE ex_invalid_id, the procedure will immediately jump to its EXCEPTION section and handle the user-defined exception.

1. Relevant knowledge points and concepts
- PL/SQL allows declaration of user-defined exceptions (ex_invalid_id EXCEPTION).
- RAISE <exception> transfers control immediately to the EXCEPTION block; following normal statements are skipped.
- Exception handlers are matched by name in the EXCEPTION section; WHEN OTHERS is a catch‑all used only if no specific handler matches.
- DBMS_OUTPUT.PUT_LINE prints the provided string to the session output.

2. Step-by-step reasoning
- The procedure is invoked with p_customer_id = 0.
- Execution reaches the IF p_customer_id <= 0 THEN RAISE ex_invalid_id; END IF; Since 0 <= 0 is true, RAISE ex_invalid_id executes.
- Control leaves the normal block immediately; the subsequent SELECT ... INTO is not executed at all.
- Execution enters the EXCEPTION section and searches for a matching handler. There is a WHEN ex_invalid_id THEN handler present.
- That handler executes DBMS_OUTPUT.PUT_LINE('Error: Invalid customer ID. Must be greater than zero.') and then the procedure ends.

3. Intermediate steps shown
- Evaluate IF (0 <= 0) → true
- Execute RAISE ex_invalid_id → jump to EXCEPTION
- Find WHEN ex_invalid_id → execute DBMS_OUTPUT.PUT_LINE with the exact string

4. Why the correct answer is correct
- The named handler for ex_invalid_id explicitly prints the shown error message. Because the exception is raised before the SELECT, no NO_DATA_FOUND or ORA-01403 condition occurs, and because a specific handler exists, you will not get an unhandled user-defined exception (ORA-06510). The output is precisely the message from the ex_invalid_id handler.

5. Why other options are incorrect
- "Error: Customer ID 0 not found." corresponds to the NO_DATA_FOUND handler, which would be triggered only if the SELECT ran and returned no rows; it never runs here.
- "An unexpected error occurred: ORA-06510..." would appear only if the raised user exception were unhandled; it is handled.
- "An unexpected error occurred: ORA-01403: no data found." is incorrect because the SELECT is skipped and NO_DATA_FOUND is not raised.

Conclusion: The output will be:
Error: Invalid customer ID. Must be greater than zero.
This matches the provided correct answer.

Consider the following PL/SQL procedure designed to retrieve customer information and handle potential errors: If get_customer_info(0) is executed, what will be the output?单项选择题

类似问题

When evaluating a new project, firms should include in the projected cash flows all of the following EXCEPT:

Provide the best rationale for what's wrong with supply chains today?

What is Blockchain and how is it relevant to supply chain management?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单