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Homework2Sol

# Homework2Sol - (COP5725(Spring2013...

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Database Management Systems (COP 5725) (Spring 2013) Instructor: Dr. Markus Schneider TA: Shuang Lin Yifan Wang Huiyuan Zhang Homework 2 Solutions Name UFID Email Address Pledge (Must be signed according to UF Honor Code) On my honor, I have neither given nor received unauthorized aid in doing this assignment. ______________________________________________ Signature For scoring use only: Maximum Received Exercise 1 20 Exercise 2 30 Exercise 3 20 Exercise 4 30 Total 100

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Exercise 1 (Knowledge Questions) [20pts] Answer the following questions: 1. What are multivalued attributes? [4pts] Multivalued attributes are those which can have many values. For example, a person can have many phone numbers etc. 2. List the basic operations of the Relational Algebra with their name and their correct symbolic notation [4pts] The basic operations are: (union), (difference), × (Cartesian product), (projection), and (selection). Further, we have the (rename) operation. 3. What are aggregate functions? Give examples of some aggregate functions in SQL. Aggregate functions are functions that take a set of values and that yield a single value in a result tuple. Examples: sum, avg, count, min, max 4. What is a 1 : m relationship set R between two entity sets E1 and E2? Each member of E1 can be associated with any number of members from E2. However, each member of E2 can be associated with only one member of E1. 5. What is generalization? “Factoring” (extracting) properties (attributes, relationships) of similar entity subclass, subtypes, categories) to a common superclass.
Exercise 2 (Relational Algebra) [30pts] Consider the following schema:

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Homework2Sol - (COP5725(Spring2013...

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