July 5, 2024 at 12:00 am
Comments posted to this topic are about the item Which is a table?
July 5, 2024 at 7:51 am
The correct answer is "Customers_b only", because the definition of primary key is that all column should be "NOT NULLABLE".
In this way you can JOIN tables by the PK without worry about NULL. UNIQUE admits NULL, so the JOIN can miss records with NULL in the KEY.
July 5, 2024 at 4:51 pm
question updated, not sure why I accepted this.
Viewing 3 posts - 1 through 2 (of 2 total)
You must be logged in to reply to this topic. Login to reply
This website stores cookies on your computer.
These cookies are used to improve your website experience and provide more personalized services to you, both on this website and through other media.
To find out more about the cookies we use, see our Privacy Policy