CS代考 INFO20003 Database Systems

INFO20003 Database Systems
Dr Farhana Q&A
INFO20003 Database Systems

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• Assignment 2 done and dusted • Peerwise is on!
• Best to start early to increase your ranking
• 3 bonus marks are well worth the effort
• Assignment 3 in Week 11
• It will be a quiz (but longer than weekly ones)
• Practice for our final exam (the long quiz as well)
• I will survey you soon on the preferred day
INFO20003 Database Systems 2

Quiz 7 walkthrough
• On the LMS…
INFO20003 Database Systems 3

Given: Reserves (R): NTuples(R) = 100, Nkeys(sid) =100,
Sailors (S): NTuples(S) =1000, Nkeys(rating) = 10 interval [1-10], age interval [0-100], Nkeys(sid)=1000
SELECT * FROM Sailors as S INNER JOIN Reserves as R ON S.SID = R.SID WHERE rating =8 and 20< age < 30; Calculate result size: NTuples(S) = 1000 NTuples(R) = 100 RF(S.SID=R.SID) = ? RF(rating) = ? RF(20CS代考 加微信: powcoder QQ: 1823890830 Email: powcoder@163.com