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Database Management Systems

CMSC 461-02 - Spring 2023

Homework 2

Due: Sunday, April 9th by 11:59:00 PM EDT (on Blackboard)

Musical Selection: Eine Kleine Nachtmusik (Serenade No. 13 in G Major) — Wolfgang Amadeus Mozart

Part 1 — 70 points

Respond to the following prompts with appropriate answers. Submit a PDF of your responses on Blackboard. Each question has an indicator of how many points it is worth.

  1. (10 points) Describe in your own words what a functional dependency is in a database design. I am not looking for the mathematical definition of a functional dependency here — I want you to describe the idea behind functional dependencies in your own words.
  2. (10 points) What is meant by a decomposition being not dependency preserving?
  3. (5 points) Give a definition of Boyce-Codd Normal Form.
  4. (5 points) Give a definition of Third Normal Form.
  5. (5 points) Why might we choose to use 3NF over BCNF when decomposing a relational schema.
  6. (15 points) As I said in class, I will not ask you to calculate F+ on a quiz or exam. But, I strongly implied it would probably show up on a homework at some point... Given the schema R = (A, B, C) and the set of functional dependencies F = { A -> BC, B -> C }, calculate F+ and Fc.
  7. (10 points) What is the difference between RAID 1 and RAID 5. Be sure to include in your description reasons that you might choose each over the other.
  8. (10 points) Describe what a "latent failure" of a data storage device is and why they can be especially destructive. How can you counteract latent failures?

Part 2 — 30 points

Write a one page (or longer) single-spaced document describing your/your team's progress on the semester project. Be sure to include any changes you have made to your project's design/goals/database schema since the project proposal. Tell me any challenges you have faced and how you've overcome them (or if you haven't yet done so). I am not looking for anything really formal here — just rather I am looking to get a sense of where you are (and to allow you to assess where you are and what you still have left to do).

Last modified Thursday, 20-Apr-2023 23:42:54 EDT