This preview shows page 1. Sign up to view the full content.
Unformatted text preview: the names of those students who should be considered for a prize, and so we select those candidates who got A in the exam. Starting from the relation Results , we obtain a relation A-Results : name address grade . . . . . . . . . Brown, B 5 Lawn Rd. A Smith, J 9 Elm St. A . . . . . . . . . In logical notation, we could write A-Results (n,a,g) if and only if Results (n,a,g) g = A In database notation we have select results where grade = A The relation A-Results gives us the names we want, but we could reduce further to get the relation PrizeCands with the single attribute: 23...
View Full Document
This note was uploaded on 01/02/2010 for the course MATH Math2009 taught by Professor Koskesh during the Spring '09 term at SUNY Empire State.
- Spring '09