# Question 1. Please select the correct statement(s) regarding a key constraint for a relation. An attribute or set of attributes satisfies a key constraint if there is no duplication of value(s) for such attribute(s) in the relation. A set of attribute(s) S is a key (super key) for a relation R if every pair of tuples in R must disagree on all the values for all attributes in S. A set of attribute(s) S is a key (super key) for a relation R if every pair of tuples in R disagree on at least one value for the attribute(s) in S. None of the above.

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A: Surrogate key is unique key and also called as synthetic primary key. Surrogate key holds anonymous…

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A:

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Q: re three reasons why the main key of a relation has to be replaced with a surrogate key?

A: Here are three reasons why the main key of a relation has to be replaced with a surrogate key.

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Q: Show that if a relation has no attribute that is functionally determined by all the other…

A: Introduction   Show that if a relation has no attribute that is functionally determined by all the…

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Q: List three conditions that suggest a surrogate key should be created for the primary key of a…

A: To be determine: List three conditions that suggest a surrogate key should be created for the…

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A: Lets see the solution.

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A: Your answer is given below.

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A: Consider the given digraph:

Q: 2 Consider the following functional dependencies for the given relation. R={A, B, C, D, E, F) AB->CD…

A: Dear Student, The answer to your question is given below -

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Q: Describe three scenarios when a surrogate key should replace a relation's primary key.

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Q: What are three reasons why the main key of a relation need to be replaced with a surrogate key?

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Q: Give two examples of a relation and their candidate key

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A: Please give positive ratings for my efforts. Thanks.   ANSWER   If there are no functional…

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Q: What are three criteria that indicate that a surrogate key for a relation's main key should be…

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Q: 1. Describe entity constraint in your own words  2. what type of key satisfies the uniqueness…

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Q: Consider a relation (p, q, r, s, t, u, v) with functional dependencies as given below: p➜q r➜s,t…

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Q: List all nontrivial functional dependencies satisfied by the relation of Figure7.18.

A: Given: List all nontrivial functional dependencies satisfied by the relation of Figure7.18.

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Q: Define three conditions under which it is appropriate to use a surrogate key in place of the primary…

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Q: If there are more than one possible candidate keys, provide some instances of relations that have…

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