Consider the following FD set on a relation E with six attributes: F, R, I, D,...
Consider the following relation: R(A,B,C,D,E) The following set of functional dependencies are ture on the relation R: FD: AB -> E, E -> D, AD -> C Which of the following sets of attributes does not functionally determine C? AC ABE BD AE AB
2. (15 points) Consider a relation with schema R(A,B,C,D) and FD= { AB->C, C->D, D- >A), what are the keys of R? Hint: Consider the 15 possible non-empty subsets of attributes. First check if a set of attributes X in R is a super key of R. If X-> R then X is superkey of R. Then X is a super key and no subset of X is a super key, then X is a key - a minimum super...
Consider the relation R with attributes: A, B, C, D, E, and F Let S be a set of functional dependencies in R such that S = { A-> B, CD-> E, C-> D]. Which of these attributes are in the closure of [C, F)?
Question 1: Functional Dependencies [7 marks Consider a relation R on attributes (A, B, C, D, E, F,G, H) and the following functional dependen- cies. B →G C →D DE →GC → EF DEF → H (a) What is the closure of [F, G, Hy? (b) List all of the candidate keys of R under the dependencies above. (c) List all of the FDs above that are 3NF violations (d) List all of the FDs above that are BCNF violations....
Here's a relation (R), its attributes and its functional dependencies (F): R(A, B, C, D, E) C D → B A → D D → C E → C What is the closure of AB ({AB}+)? What is the closure of F (F+)? [ set of closures for all LHS][each LHS on one line] What is the minimal set (cover) for F? Provide a key for relation R (a minimal set of attributes that can determine all attr.) Decompose the...
Dependency Very Good dependency (key dependency) : XA where Table Very good If all dependencies in a table are '"very good", the table is in BCNF X is a candidate key Good Good dependency: X-> A where If all dependencies in a table are "very good" or "good", the table is in 3NF X is not a candidate key X is a part of a candidate key A is prime attribute Bad Bad dependency (Transitive Dependency): X A where If...
Consider a relation R with ve attributes A, B, C, D, and E. You are given the following functional dependencies: A->B, BC->E, and ED->A. (a) List all keys for R. (10 points) (b) Is R in BCNF? If it is, explain why. If is not, decompose it into a collection of BCNF relations. (20 points) (c) Is R in 3NF? If it is, explain why. If it is not, convert it into a collection of 3NF relations. (20 points)
Consider the relation R(A, B, C, D, E), where it is known that the only keys are {A, C, D} and {D, E}: Give a set of functional dependencies that will make {A, C, D} and {D, E} be the only keys of R. This set should be such that if you delete any FD, then the keys of R will be something other than {A, C, D} and {D, E}.
Consider the schema R = (A, B, C, D, E) and let the following set F of functional dependencies holdforR: F = {A -> BC, CD -> E, C -> A, B -> D,} 1) Prove or disprove ADE is in the closure of F. A proof can be made by using inference rules IR1 through IR3. A disproof should be done by showing a relational instance (counter example) that refutes the rule. 2) What are the candidate keys of...
please do question 4.
Note that we follow the convention of denoting the set of attributes {A, B, C} by ABC when we write FDs but not when we write schemas. Given the following set set F of FDs on schema R= (A, B, C, D, E,G): A + BC AB + CD B +C E →D G +C EG → AD Answer the following questions. Questions 1-4 require a formal proof or disproof. A proof may be given either...