It is possible to write tuple calculus expressions that generate infinite relations. For example {t/~te R} results in an infinite relation if the domain of any attribute of relation R is infinite. To guard against the problem, we restrict the set of allowable expressions to safe expressions.
Mwalimu Bonface answered the question on March 1, 2018 at 10:33
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March 1, 2018
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A union, intersection or difference can only be performed between two relations if they are type compatible. What is meant by type compatibility? Give an example of two type compatible and two non type compatible relations?
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March 1, 2018
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March 1, 2018
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February 28, 2018
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February 28, 2018
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Date posted:
February 28, 2018
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Date posted:
February 28, 2018
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Date posted:
February 28, 2018
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February 28, 2018
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February 28, 2018
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Date posted:
February 28, 2018
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February 28, 2018
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February 28, 2018
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With the use of internet, email has become part and parcel of communication. Briefly describe the negative impact it brings.
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With the use of internet, email has become part and parcel of communication. Briefly describe the negative impact it bring.
Date posted:
February 28, 2018
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The internet is making the world to be a global village with easier communication of email. Describe the advantages of using email for communication.
Date posted:
February 28, 2018
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Answers (1)