Structure of the ORDERITEMS table

-Based on the structure of the ORDERITEMS table,which of the following commands will add a NOT NULL constraint to the ISBN column?
A) ALTER TABLE orderitems ADD (isbn NOT NUL
L);
B) ALTER TABLE orderitems ADD NOT NULL (isbn);
C) ALTER TABLE orderitems ADD isbn NOT NULL;
D) none of the above

Question

​Structure of the ORDERITEMS table
 
-Based on the structure of the ORDERITEMS table,which of the following commands will add a NOT NULL constraint to the ISBN column?​
A) ​ALTER TABLE orderitems ADD (isbn NOT NUL
L); 
B) ​ALTER TABLE orderitems ADD NOT NULL (isbn); 
C) ​ALTER TABLE orderitems ADD isbn NOT NULL; 
D) ​none of the above

Quizplus · Accepted Answer

To add a NOT NULL constraint to an existing column, the syntax typically involves modifying the column rather than adding a new column or constraint directly. None of the provided options correctly follow the syntax for altering an existing column to add a NOT NULL constraint. The correct approach usually involves using ALTER TABLE ... MODIFY or ALTER TABLE ... ALTER COLUMN syntax, depending on the SQL dialect, which is not represented in any of the given choices.

​Structure of the ORDERITEMS Table

Structure of the ORDERITEMS Table