oracle ocp 19c考题，科目082考试题(17)-using an invisible column

17. Examine the following command:

CREATE TABLE (

prod_id number(4),

Prod_name varchar2 (20),

Category_id number(30),

Quantity_on_hand number (3) INVISIBLE);

Which three statements are true about using an invisible column in t he PRODUCTS table?

A. The %ROWTYPE attribute declarations in PL/SQL to access a row will not display the invisible column in the output.

B. The DESCRIBE commands in SQL *Plus will not display the invisible column in t he output.

C. Referential integrity constraint cannot be set on t he invisible column.

D. The invisible column cannot be made visible and can only be marked as unused.

E. A primary key constraint can be added on t he invisible column.

source : cuug

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来源： https://www.cnblogs.com/alice9313/p/15825306.html