CMSC424-0201: Homework 1Due: February 9, 2006Note: The amount of space provided is an upper bound. You shouldn’t need that much space formost of the questions.1. You are asked to design a database for maintaining information about viewers’ TV watchinghabits, and also their friend circles (as a social network). Begin with constructing an E/Rdiagram. Here are the conceptual requirements/domain knowledge, and some simplifyingassumptions. [2 pts](a) Assume the maintained information is only about past. Don’t worry about storinginformation about future episodes.(b) Episode numbers or episode names are not unique across TV Shows.(c) A viewer watches an episode as a whole; ie. she either watches an episode or doesn’t.No partial watching is allowed. Note that she may not watch all episodes of a TV Show.(d) Assume a single market, and a single airing of each episode. The time at which theepisode aired must be maintained.(e) Obviously a viewer can only watch one show at a time.(f) Assume simple symmetric friend relationships.You might want to begin with three entity sets: (1) TV Show, (2) Episode, (3) Viewer.TV ShowViewerEpisode2. Why is the entity set Episode drawn differently than the other two entity sets ? [1 pts]3. Chapter 6.3.3 discusses what are called participatory constraints. Write down a relationshipin the above E/R diagram where you might want to add such a constraint. [1 pts]4. Discuss how you might want to specialize (Chapter 6.7.1) the TVShow entity set from above.What are the advantages of this specialization ? [1 pts]5. Some conceptual models are not rich enough to model certain domain knowledge. It isnot obvious how to model Assumption (e) from above in the E/R model (at least using theconstructs discussed so far). Can it be done ? Can you give an argument as to why or whynot ? [1 pts]6. What are the disadvantages of not being able to model such a constraint or such a piece ofdomain knowledge in the conceptual model ? [1 pts]7. Identify one or two other pieces of domain knowledge for this application that might mostoften be true, but would be hard to model with the constructs we have seen so far. [1 pts]8. I want to recommend new shows to viewers based on both what they have watched, and whatothers have watched. Describe some ways you might want to use the friend circle for thispurpose. Try to be specific in your suggestions. [1 pts]9. Define the concept of aggregation (Chapter 6.7.5). Give an example of where this might beuseful. You can use any example other than the one presented in Chapter 6.7.5. If you wantto do this for the TiVo application above, consider modeling TV Channel information, andmodeling the fact that different viewers may watch the same episode on different channels(or otherwise consider re-runs). [2 pts]10. Convert the above E/R diagram into a relational schema. Underline primary keys. [2 pts]How much time (approximately) did you need to finish this exam ? Please be honest; thiswon’t affect your grade in absolutely any
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