Question

Before the usage of .................. table command to add a primary key, one needs to make sure that the field is ...........

• A. ALTER, NOT NULL
• B. Create, NOT NULL
• C. Update, NOT NULL
• D. Update, NULL

Hint:

Ensure that the column you intend to use as a primary key does not allow NULL values before adding the primary key constraint.

Answer 1

The Correct Option is A

To add a primary key to a table, the column used for the key must have unique values, and it must not allow NULL values. The ALTER command is used to modify a table, so the correct answer is ALTER with the constraint NOT NULL.