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Start learning 50% faster. Sign in nowA candidate key is a minimal superkey that uniquely identifies tuples in a relation. A fundamental property of candidate keys is that they cannot contain NULL values. This is because NULL signifies "unknown" or "not applicable," and allowing NULL values in a candidate key would mean that we cannot guarantee the uniqueness of the key. If a candidate key were allowed to have NULL values, there could be ambiguity in identifying records, which violates the principle of uniqueness and reliability. For example, if two tuples share the same key attributes except for one containing a NULL, the database cannot assert the uniqueness of these tuples. Why Other Options Are Incorrect:
108 ÷ ? + 156 ÷ √144 = √64 × 2
8 × 9 + ? – 6 × 11 = 12 × 8
If x + y + 3 = 0, then find the value of x3 + y3 – 9xy + 9.
Simplify the following expression:
(400 +175) ² - (400 – 175) ² / (400 × 175)
? = 6.25% of 240 + 252 + 172 – 16 × 17
1200% of 18 + √1600 + 62 = ?2 + (90 of 0.4)
8 × 25% of ? = 400
222 - 122 + 162 = (?)2 – 29