CMSC424 0201 Homework 1 Due February 9 2006 Note The amount of space provided is an upper bound You shouldn t need that much space for most of the questions 1 You are asked to design a database for maintaining information about viewers TV watching habits and also their friend circles as a social network Begin with constructing an E R diagram Here are the conceptual requirements domain knowledge and some simplifying assumptions 2 pts a Assume the maintained information is only about past Don t worry about storing information 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 the episode 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 Viewer TV Show Episode 2 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 relationship in 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 is not obvious how to model Assumption e from above in the E R model at least using the constructs discussed so far Can it be done Can you give an argument as to why or why not 1 pts 6 What are the disadvantages of not being able to model such a constraint or such a piece of domain knowledge in the conceptual model 1 pts 7 Identify one or two other pieces of domain knowledge for this application that might most often 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 what others have watched Describe some ways you might want to use the friend circle for this purpose 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 be useful You can use any example other than the one presented in Chapter 6 7 5 If you want to do this for the TiVo application above consider modeling TV Channel information and modeling 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 this won t affect your grade in absolutely any way
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