UMBC
Spring 2006
CMSC461
Database Management Systems
Homework1 -- Due beginning of class on 22nd of February.
All homeworks should be done independently.
Reading assignment : Ch6 (5th edition) or Ch2 (4th edition) (you may
skip the section on UML)
Construct an E-R diagram for the following enterprises.
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For each, show clearly all entity and relationship sets, and their attributes.
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For each relationship set, indicate the mapping cardinalities.
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For each set, identify the primary key or keys.
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Convert the E-R diagram into tables.
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Use the mapping cardinalities to eliminate redundant tables.
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List assumptions if any.
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Simplifying assumptions also lead to limitations on your design. Indicate
any limitations.
1. On-line bookstore (like Amazon.com)
2. On-line auction site (like ebay)
3. A car insurance company
4. Department of motor vehicles
Note : develop your design incrementally. Don't make it too simplistic
but at the same time, do not generate a highly detailed model either. It
is enough if each application contains about 5-10 entity sets and about
half as many relationship sets. Take a look at the following
ER
diagrams.