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Unformatted text preview: 1 Relational Database Design Part II CPS 116 Introduction to Database Systems 2 Announcements (Tue. Sep. 13) ¡ Homework #1 due in one week ¢ You should have started by now ¡ Course project description available! ¢ Choice of “standard” or “open” ¢ Team of size 1-4, but 1- and 4-person teams need approval from me ¢ Two milestones + demo/report ¢ Milestone #1 due in one month, right after fall break 3 Database design steps: review ¡ Understand the real-world domain being modeled ¡ Specify it using a database design model (e.g., E/R) ¡ Translate specification to the data model of DBMS (e.g., relational) ¡ Create DBMS schema ) Next: translating E/R design to relational schema 4 E/R model: review ¡ Entity sets ¢ Keys ¢ Weak entity sets ¡ Relationship sets ¢ Attributes on relationships ¢ Multiplicity ¢ Roles ¢ Binary versus N-ary relationships • Modeling N-ary relationships with weak entity sets and binary relationships ¢ ISA relationships 5 Translating entity sets ¡ An entity set translates directly to a table ¢ Attributes → columns ¢ Key attributes → key columns Students Courses CID title Enroll SID name grade Student ( SID , name ) Course ( CID , title ) 6 Translating weak entity sets ¡ Remember the “borrowed” key attributes ¡ Watch out for attribute name conflicts Building ( building_name , year ) Rooms ( building_name , room_number , capacity ) Seats ( building_name , room_number , seat_number , left_or_right ) Rooms In Buildings name year number capacity In Seats number L/R? 2 7 Translating relationship sets ¡ A relationship set translates to a table ¢ Keys of connected entity sets...
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This document was uploaded on 01/17/2012.
- Spring '09