代写schema留学生、代做R设计、代写R编程语言、代做BCNF

日期：2019-03-26 10:02

Exercise 1

Consider a relation with schema R (A, B, C, D) and FDs the set F:

F= {AB→C C→D D→A }

a.(10%) Find all the candidate keys of R.

b.(5%) Indicate all BCNF violations for R.

c.(10%) Decompose the relations into collections of relations that are in BCNF.

d.(5%) Indicate which dependencies, if any, are not preserved by the BCNF decomposition.

Exercise 2

Consider a relation with schema R (A, B, C, D) and FDs the set F:

F ={ A→B

       A→C

      C→D }

a.(5%) Determine the set of all candidate keys for the relation schema.

b.(5%) Determine the highest normal form (no NF, 1NF, 2NF, 3NF, BCNF) that the relation schema is in. Explain your answer.

c.(10%) Decompose the relation schema into new relation schemas that satisfy the next higher normal form.

d.(10%) Show the minimal covers of functional dependencies for the decomposed relation schemas.

e.(10%) List the candidate keys of the decomposed relation schemas.

f.(10%) Prove that the decomposition is a lossless join decomposition and/or dependency preserving.