Last answered:

01 Aug 2022

Posted on:

23 Jul 2022

1

Explanations to questions 3 and 4 are inconsistent?

The explanation to question 3 is that UNIQUE allows us to put just one NULL value. Then, the answer to question 4 should be that we cannot add a record with another NULL value for ID, because the ID must be unique! Why the correct answer to question 4 is another one, instead? Thank you

2 answers ( 0 marked as helpful)
Instructor
Posted on:

25 Jul 2022

0

Hi Alessandro!
Thanks for reaching out.

Could you please explain which exercises do you refer to? Thank you.

Looking forward to your answer.
Best,
Tsvetelin

Posted on:

01 Aug 2022

0

Good morning. I refer to "Practice Exam: 1" at the end of chapter 9. The explanation to question 3 says "the former allows us to put only one NULL value", and it refers to UNIQUE keys. Is the explanation to question 3 wrong or is the answer to question 4 wrong? I guess it's the former. Thank you

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