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← Logic & PuzzlesWhat happens to a database query result when the set theory principle of 'union' combines two tables with completely disjoint sets of primary keys?
A)A smaller set is produced
B)Only common entries are included
C)A larger, combined set results✓
D)An empty set will always result
💡 Explanation
A 'union' operation, by set theory definition, creates a new set containing all distinct elements from both original sets; because the primary keys are disjoint, no overlap exists, therefore the resulting set contains all elements from both, forming a larger set, rather than filtering or reducing the set.
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