Database Concepts (8th Edition)
8th Edition
ISBN: 9780134601533
Author: David M. Kroenke, David J. Auer, Scott L. Vandenberg, Robert C. Yoder
Publisher: PEARSON
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Expert Solution & Answer
Chapter 2, Problem 2.26RQ
Explanation of Solution
Meaning of the Equation:
The given expression is,
(D, E)->F
Explanation:
The meaning of the following equation is:
- Given the value for both D and E simultaneously, represented as composite (D, E), user can determine the value of F.
- If one of the values of D or E is not given, user cannot determine the value of F.
- The Composite (D, E) is the determinant of F.
- F is functionally dependent on the composite (D, E).
- It is a composite key.
Example:
- For a table Employee containing attributes ‘employee_id’, ‘employee_name’ and ‘employee_department’, it is observed that user can fill an online form asking to enter the ‘employee_name’ and ‘employee_department’ simultaneously and the
Database Management System (DBMS) searches the employee database and retrieves the information about employee id .
Therefore, expression can be (employee_name, employee_department) -> (employee-id)...
Expert Solution & Answer
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Students have asked these similar questions
Explain the meaning of the following expression: (D, E) → F Given this expression, tell if it is also true that: D → F and: E → F
Consider two operators A and B. What does [A, B] equal? (A) AB−BA
(B) BA−AB(C) AB+BA(D) BA+AB(E) None of the above.
Laws of logic:
Could you make sure this question is proven correctly using the laws.
Chapter 2 Solutions
Database Concepts (8th Edition)
Ch. 2 - Prob. 2.1RQCh. 2 - Define the term entity, and give an example of an...Ch. 2 - Prob. 2.3RQCh. 2 - Prob. 2.4RQCh. 2 - Prob. 2.5RQCh. 2 - Prob. 2.6RQCh. 2 - Prob. 2.7RQCh. 2 - Prob. 2.8RQCh. 2 - Prob. 2.9RQCh. 2 - Define the term unique key and give an example.
Ch. 2 - Prob. 2.11RQCh. 2 - Prob. 2.12RQCh. 2 - Define the terms candidate key and primary key....Ch. 2 - Describe four uses of a primary key.Ch. 2 - Prob. 2.15RQCh. 2 - Prob. 2.16RQCh. 2 - Prob. 2.17RQCh. 2 - Explain the term foreign key, and give an example.Ch. 2 - Prob. 2.19RQCh. 2 - Prob. 2.20RQCh. 2 - Explain three possible interpretations of a null...Ch. 2 - Give an example of a null value (other than one...Ch. 2 - Prob. 2.23RQCh. 2 - Prob. 2.24RQCh. 2 - Prob. 2.25RQCh. 2 - Prob. 2.26RQCh. 2 - Prob. 2.27RQCh. 2 - Define the term primary key in terms of functional...Ch. 2 - Prob. 2.31RQCh. 2 - Examine the data in the Veterinary Office...Ch. 2 - Prob. 2.33RQCh. 2 - Describe a modification problem that occurs when...Ch. 2 - Prob. 2.35RQCh. 2 - Prob. 2.36RQCh. 2 - Prob. 2.37RQCh. 2 - Apply the normalization process to the Veterinary...Ch. 2 - Prob. 2.39ECh. 2 - Apply the normalization process to the Veterinary...
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- A propositional logic expression is in full disjunctive normal form if it is a disjunction (i.e., a term that uses only the 'OR' operator) of one or more conjunctions (i.e., terms that uses only the 'AND' operator), and each of the variables in the expression appears once (and only once) in each conjunction. Using this definition, what is the full disjunctive normal form of the expression below? (¬((P V (¬R)) → (¬Q))) Select one: (¬P AQA¬R) V (PA¬Q A ¬R) V (PAQA¬R) (¬P ^¬QA¬R) V (¬P ^ Q ^ ¬R) V (P ^ Q A R) (¬P A¬QA ¬R) V (¬P AQA¬R) V (PAQA¬R) O none of these options (¬P AQA¬R) V (PAQA¬R) V (PAQA R) (¬P AQA ¬R) V (¬P ^QA R) V (P AQA R)arrow_forwardDefinition of 3SAT : In the 3SAT problem, the input is a Boolean expression formed by m clause and n variables (each variable x can have a positive literal x and negative literal x). Each clause formed by disjunction of threeliterals and the formula is formed by the conjunction of the m clauses. For example, the following formulais an instance of the 3SAT problem: (x1 ∨ x2 ∨ x3) ∧ (x1 ∨ x2 ∨ x3) ∧ (x1 ∨ x2 ∨ x3), which is formed by 3 variables x1, x2, x3 and three clauses. The objective is to find an assignment of Boolean values to variables to satisfy the formula. In the example above, one possible satisfying assignment is to let x1 to be false and x2, x3 to be true. Problem : A 2SAT formula is a conjunction of clauses like a 3SAT formula, except that each clause is a disjunction of 2 literals (rather than 3). For example (x1 ∨ x2) ∧ (x2 ∨ x3) ∧ (x3 ∨ x1) is a 2SAT formula.Use consistency model to provide a 2SAT formula consistent with the following labelled data (or specifythat…arrow_forwardWhy is it easier (in run time) to satisfy Disjunctive Normal Form (DNF) than Conjunctive Normal Form (CNF) even so CNF can be converted to DNF?arrow_forward
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