Functional Dependencies and Minimal Cover
Consider a relation R (ABCDEFGH) with the following functional dependencies:
ACD –> EF
AG –> A
B –> CFH
D –> C
DF –> G
F –> C
F –> D
Find minimal cover and identify all possible candidate keys. In order to receive full credit, please list each step taken and the rules that you applied.
Rubric for grading
Functional Dependencies and Minimal Cover Rubric
CriteriaRatingsPts
Functional Dependencies
All non-trivial functional dependencies have been correctly identified. There are no missing or extra functional dependencies that do not fit either the data or assumptions made.
18 pts
There are 1-2 missing non-trivial functional dependencies based on the sample relation instance and assumptions made.
16 pts
There are several missing and/or extra non-trivial functional dependencies based on the sample relation instance and assumptions made.
14 pts
There are many missing and/or extra non-trivial functional dependencies. Several trivial dependencies are present. The functional dependencies are not clearly labeled.
12 pts
18 pts
Assumptions
All assumptions about the sample relation instance are clearly stated and match the functional dependencies identified.
18 pts
Assumptions have been made about the sample relation instance, but not explicitly stated.
16 pts
Assumptions about the sample relation instance are stated, but do not match the functional dependencies identified.
14 pts
Unnecessary assumptions are made that do not fit the sample relation instance or the functional dependencies identified.
12 pts
18 pts
Minimal Cover
Armstrong’s Axioms have been correctly applied to find minimal cover. Redundant attributes and redundant dependencies have been systematically removed.
36 pts
Armstrong’s Axioms have been correctly applied to find minimal cover. However, the solution still includes 1-2 redundant attributes or dependencies.
32 pts
Armstrong’s Axioms have been incorrectly applied. The solution includes several redundant attributes, redundant dependencies, and one or more incorrect dependencies.
28 pts
Armstrong’s Axioms have been incorrectly applied and several steps are missing. The solution includes many redundant or incorrect attributes and dependencies.
24 pts
36 pts
Candidate Keys
All possible candidate keys have been correctly identified from minimal cover.
18 pts
The process to identify candidate keys is correct but 1-2 keys are missing.
16 pts
The process to identify candidate keys is incorrect resulting in wrong candidate keys.
14 pts
No attempt has been made to identify candidate keys.
12 pts
18 pts
Total Points: 90
