hw1.365

# hw1.365 - CPE 365 Introduction to Databases Fall 2007...

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Unformatted text preview: CPE 365 Introduction to Databases Fall 2007 Homework 3 Due: Tuesday, October 16, in class Problem 1 Consider the following relations: R : A B C b c 3 a c 2 c a 3 b b 1 c a 4 b a 2 S : A B C c c 2 c a 3 b b 4 a b 3 b c 3 a a 1 T : B D E F a a 1 2 c d 2 4 b b 3 2 d b 3 2 a d 2 3 b c 4 1 d a 1 4 W : C D 1 a 2 b 3 c 4 d For each of the following queries: (1) compute the answer, (2) draw the query tree. a. R ∩ S b. S- R c. R- S d. π A,B ( R ) e. π B,A ( R ) ∪ π B,A ( S ) f. π C,B ( R )- π C,B ( S ) g. π C ( W ) × π B ( S ) × π F ( T ) h. σ B = c ( R ) i. σ A negationslash = B ( S ) j. π B,D ( σ F ≤ E ( T )) k. σ A = D ( π A ( R ) × W ) 1 l. σ A = b ∧ C> 1 ( R ) ∪ σ B = b ∨ C< 3 ( S ) m. σ ¬ ( E =3) ( T ) n. π A,B,R.C,D ( σ R.C = W.C ( R × W )) o. W ⊲⊳ R p. W ⊲⊳ R.C = W.C R q. T ⊲⊳ F = C W r. R ⊲⊳ S s. R ⊲⊳ R.B = S.A S t. ( R ⊲⊳ T ) ⊲⊳ π A,C,D ( S ⊲⊳ W ) u. π T 1 .D,T 2 .B ( T ⊲⊳ T 1 .D = T 2 .B T ) v. π B,D,E ( σ F>C...
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hw1.365 - CPE 365 Introduction to Databases Fall 2007...

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