CS 4250: Project Part 4

Hardcopy/email due at midnight (email only) or 4pm (paper or email) on (new) Wednesday, April 17, 2013. (old) Monday, April 15, 2013. (Email: subject line of "cs4250, project part 4". PDF, plain text or MS Word only.)

1. (0 pts) List all the relations in this schema. (An up-to-date copy of your "create table" statements would be fine. These tables should have been corrected based on feedback from Part 3, if necessary.)

2. List all reasonable, non-trivial functional dependencies (FDs) that apply to your design.

   For readability: List all FDs with only one attribute on the right hand side. List all the FDs vertically, one FD per line. To the right of each FD, list the relations/tables it involves, in alphabetical order.

   If you use the single letter per field convention in our textbook, be clear about which letter corresponds to which field in which relation at all times.

3. Are all the relations in your chosen schema in 3NF? Are they in BCNF? Explain both answers. Do not make a blanket statement about all relations; make a neat list of your relation names and, for each one, which normal form it is (or is not) in.

   If any of your relations are not in BCNF, normalise them to BCNF. If you choose to normalise your relations only until they are in 3NF, explain your reasons (e.g., the amount of redundancy introduced is limited or some other valid reason). Notice that if you decide to go ahead with normalization, you will have to list the violating FDs for each of your relations and explain why you think they violate 3NF and/or BCNF.

Most of the assignment points will be given for your clear, well-reasoned explanations, demonstrating clear understanding of what FDs and normal forms are and how your FDs and relations interact with the normal forms.

Required but not graded: Include one sentence per group member summarizing each group member's contribution to Project Part 4. These sentences are not for part of any student grades. They will be used to monitor group dynamics, and to try to intercede in troubled groups (if any) before troubles get out of hand.

Question: The second part seems to imply that we can "get away without doing normalization". Is that true? Why do you have the clause "if you decide to go ahead with normalization"?

Answer: There is no escaping from normalization! We haven't spent so much time on it without requiring you to do it for your project. First realize that you have to bring your relations into 3NF, come what may.

There are some exceptional cases where normalization to BCNF can be skipped and you can actually leave the relation in 3NF. However, such cases are far and few in between. You must have a truly sound reason for not doing BCNF normalization.

Last modified: 4/8/2013