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132 hints

# 132 hints - QBE conditional box πNAME(PERSON −...

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List at lowest All sailor.rating >= s.rating Need domain calculus for qbe {s: name | for all s in sailor [s.rating >= t.rating]} If no need for a, create some E a that is actor in movie(t,d,a) but you want t,d don’t need a, just make a random a Create variable x if no need for it in the query. Define variables x: rating, y: rating Can use <, > Sailor(sn1,x) ^ sailor(sn2, y) ^ x < y
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Unformatted text preview: QBE conditional box πNAME (PERSON) − πNAME (σAGE<AGE’ (PERSON><δ AGE→AGE’ (πAGE (PERSON)))) Slide 36 calculus algebra pdf q: πAB (σB=5 (R)) πBC (πAB (R) πAC (σB=5 (R))) When doing tableau minimization, if pi ac , then project E b 1 then change all of the next b vars to b1. If theres is a quantifier sigma b = 5 then do ^ b 1 = 5....
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