Relational Schema Design
Anomalies:
• Redundancy        = repeat data
• Update anomalies = Fred moves to “Bellvue”
• Deletion anomalies = Fred drops all phone numbers:
 what is his city ?
Recall set attributes (persons with several phones):
SSN à Name, City,    but not SSN à PhoneNumber
Westfield
908-555-1234
987-65-4321
Joe
Westfield
908-555-2121
987-65-4321
Joe
Seattle
206-555-6543
123-45-6789
Fred
Seattle
206-555-1234
123-45-6789
Fred
City
PhoneNumber
SSN
Name