Consider the relation "enrolled(student, course)" in which (student, course) is the primary key, and the relation "paid(student, amount)" where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Given the following four queries:

- a)All queries return identical row sets for any database
- b)Query2 and Query4 return identical row sets for all databases but there exist databases for which Query1 and Query2 return different row sets.
- c)There exist databases for which Query3 returns strictly fewer rows than Query2
- d)There exist databases for which Query4 will encounter an integrity violation at runtime.

Correct answer is option 'B'. Can you explain this answer?

Related Test: SQL MCQ Quiz - 1

By
Apurva Patel
·
just now ·Computer Science Engineering (CSE)

This discussion on Consider the relation "enrolled(student, course)" in which (student, course) is the primary key, and the relation "paid(student, amount)" where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Given the following four queries:Q. Which one of the following statements is correct?a)All queries return identical row sets for any databaseb)Query2 and Query4 return identical row sets for all databases but there exist databases for which Query1 and Query2 return different row sets.c)There exist databases for which Query3 returns strictly fewer rows than Query2d)There exist databases for which Query4 will encounter an integrity violation at runtime.Correct answer is option 'B'. Can you explain this answer? is done on EduRev Study Group by Computer Science Engineering (CSE) Students. The Questions and
Answers of Consider the relation "enrolled(student, course)" in which (student, course) is the primary key, and the relation "paid(student, amount)" where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Given the following four queries:Q. Which one of the following statements is correct?a)All queries return identical row sets for any databaseb)Query2 and Query4 return identical row sets for all databases but there exist databases for which Query1 and Query2 return different row sets.c)There exist databases for which Query3 returns strictly fewer rows than Query2d)There exist databases for which Query4 will encounter an integrity violation at runtime.Correct answer is option 'B'. Can you explain this answer? are solved by group of students and teacher of Computer Science Engineering (CSE), which is also the largest student
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Consider the relation "enrolled(student, course)" in which (student, course) is the primary key, and the relation "paid(student, amount)" where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Given the following four queries:Q. Which one of the following statements is correct?a)All queries return identical row sets for any databaseb)Query2 and Query4 return identical row sets for all databases but there exist databases for which Query1 and Query2 return different row sets.c)There exist databases for which Query3 returns strictly fewer rows than Query2d)There exist databases for which Query4 will encounter an integrity violation at runtime.Correct answer is option 'B'. Can you explain this answer? over here on EduRev! Apart from being the largest Computer Science Engineering (CSE) community, EduRev has the largest solved
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