Is there a commutativity transformation for the projection operator? Explain.
What will be an ideal response?
No. Commutativity of projection means
?attr1(?attr2(R)) = ?attr2(?attr1(R))
The left side requires attr1 ? attr2 and the right side requires attr2 ? attr1. This is impossible unless attr1 = attr2.
Computer Science & Information Technology
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Computer Science & Information Technology
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Computer Science & Information Technology
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