分类： Oracle
2022-01-20 10:29:39
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
