Ch5_SQL - SQL Queries Programming Triggers Chapter 5...

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1 Database Management Systems, R. Ramakrishnan and J. Gehrke INFSCI2710 Instructor: Vladimir Zadorozhny SQL: Queries, Programming, Triggers Chapter 5 Instructor: Vladimir Zadorozhny [email protected] Information Science Program School of Information Sciences, University of Pittsburgh 2 Database Management Systems, R. Ramakrishnan and J. Gehrke INFSCI2710 Instructor: Vladimir Zadorozhny Example Instances sid sname rating age 22 dustin 7 45.0 31 lubber 8 55.5 58 rusty 10 35.0 sid sname rating age 28 yuppy 9 35.0 31 lubber 8 55.5 44 guppy 5 35.0 58 rusty 10 35.0 sid bid day 22 101 10/10/96 58 103 11/12/96 R1 S1 S2 We will use these instances of the Sailors and Reserves relations in our examples. If the key for the Reserves relation contained only the attributes sid and bid , how would the semantics differ?
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