STQC-NIELIT STA 2021
October 19, 2023UGC NET CS 2016 Aug- paper-3
October 19, 2023Constraints
| Question 1 |
Which of the following constraints enforces that the value of the primary key cannot be Null?
| Key Constraint | |
| Foreign key constraint | |
| Entity integrity constraint | |
| Domain constraint |
Question 1 Explanation:
The entity integrity constraint states that primary key value can’t be null. This is because the primary key value is used to identify individual rows in relation and if the primary key has a null value, then we can’t identify those rows.
Correct Answer: C
Question 1 Explanation:
The entity integrity constraint states that primary key value can’t be null. This is because the primary key value is used to identify individual rows in relation and if the primary key has a null value, then we can’t identify those rows.
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