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Question 19Asked in UGC NET Computer Science, December 2014 (Paper II & III, Selected Questions)

Which of the following is true? I. Implementation of self-join is possible is SQL with table alias

Which of the following is true? I. Implementation of self-join is possible is SQL with table alias II. Outer-join operation is basic operation in relational algebra III. Natural join and outer join operations are equivalent.
  1. AI and II are correct
  2. BII and III are correct
  3. COnly III is correct
  4. DOnly I is correct
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Correct answer: (D) Only I is correct

Explanation

Only I is correct: a self join is implemented on a single table using alias names. Outer join is not a basic relational algebra operation, and natural join and outer join are not equivalent.

From UGC NET Computer Science PYQ, December 2014 (Paper II & III, Selected Questions)

This is question 19 of UGC NET Computer Science PYQ, December 2014 (Paper II & III, Selected Questions). See all questions of this paper with answers, or attempt the paper as a timed online test to get your score and all-India rank.