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多項(xiàng)選擇題

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 the 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 the output.
C. Referential integrity constraint cannot be set on the 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 the invisible column.

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