Suppose that you decompose a schema R (A, B, C, D, E) into two schemas as...
Suppose that you decompose a schema R (A, B, C, D, E) into two schemas as below:
R1 (A, B, C)
R2 (C, D, E)
Show that this decomposition is not a lossless join decomposition.
Hint: Take a suitable Relation, r, for the Schema R and show that r is a lossy join decomposition.
Homework Answers
A decomposition {R1, R2} is a lossless-join decomposition
if R1 ∩ R2 → R1 or R1 ∩ R2 → R2 where THis after intersection result must be a candidate key
so
R1 ∩ R2 = Φ
and Φ canot be a candidate key so it is not a lossless join decomposition.
Add Answer to:
Suppose that you decompose a schema R (A, B, C, D, E) into two
schemas as...
consider the schema R-(A,B.C,D,E) and the following set F of functional dependencies holds on R ABC...
consider the schema R-(A,B.C,D,E) and the following set F of functional dependencies holds on R ABC CD-E B- D E-A Problem 2. Suppose that we decompose the relation schema R into R, -(A, B, C) and R, (C, D,E). Show that this decomposition is not a lossless-join decomposition.
Find the decopmosition of R into R1(A, B, C), R2(B, C,D ) and R3(C, D, E)...
Find the decopmosition of R into R1(A, B, C), R2(B, C,D ) and
R3(C, D, E)
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CDAE, C-D, D-E} The decomposition of R into R1(A, B, C), R2(B, C, D) and RP(C, D, E) is (2 Points) Select one: Lossy and Not Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Dependency Preserving. Lossless and Dependency Preserving.
can you answer part e of the question Q.31 Answer the following questions (a) Explain difference between lossy decomposition and lossless decomposition (b) If you write a SQL statement to inner jo...
can you answer part e of the question
Q.31 Answer the following questions (a) Explain difference between lossy decomposition and lossless decomposition (b) If you write a SQL statement to inner join the following two tables based on Plocation value as inner join condition, is the result table lossy or lossless? (Explain why?) EMP LOCS P.K EMP PROJ1 Hours Pname Plocation Р.К. (c) Given a relation schema R ={SSN, Ename, Pnumber, Pname, Plocation, Hours) R is decomposed to R1, R2,...
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, D-E} The decomposition of...
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, D-E} The decomposition of Rinto R1(A, B, C), R2(B, C, D) and R3(C, D, E) is 2 Points) Select one: Lossless and Dependency Preserving. Lossy and Not Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Dependency Preserving.
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, D-E} The decomposition of...
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, D-E} The decomposition of Rinto R1(A, B, C), R2(B, C, D) and R3(C, D, E) is 2 Points) Select one: Lossless and Dependency Preserving. Lossy and Not Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Dependency Preserving.
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, DE} The decomposition of...
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, DE} The decomposition of R into R1(A, B, C), R2(B, C, D) and R3(C, D, E) is (2 Points) Select one: Lossy and Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Not Dependency Preserving. Lossless and Dependency Preserving.
Consider the schema R=(A, B, C, D, E) and let the following set F of functional...
Consider the schema R=(A, B, C, D, E) and let the following set F of functional dependencies hold for R: F= {A → BC, CD → E, B D } Problem 3 Suppose that the schema R=(A, B, C, D, E) is decomposed into R/ - (A, B, C) and R=(A, D, E). Show if this decomposition is a lossless decomposition with respect to the given set of functional dependencies F.
Given the following Schema S = (R, FD) where R = (A, B, C, D, E, F) and FD contains the following...
Given the following Schema S = (R, FD) where R = (A, B, C, D, E, F) and FD contains the following dependencies: A -> BC B ->C C -> D D ->E C -> E E -> F DE -> F C -> F 1. Find a minimal cover of F 2. Find a key for the schema 3. Find a 3N decomposition of the schema that satisfies the lossless join decomposition and dependency preservation properties 4. Find a...
Given the following relation schemas and the sets of FD's: a- R(A,B,C,D) F={ABẠC,C7D, D´A, BC+C} b-...
Given the following relation schemas and the sets of FD's: a- R(A,B,C,D) F={ABẠC,C7D, D´A, BC+C} b- R(A,B,C,D) F={BẠC, BD, AD>B} C- R(A,B,C,D) F={AB-C, DC+D, CD+A, AD+B} d- R(A,B,C,D) F={AB=C, C+D, D™B, DE} e- R(A, B, C, D, E) F= {AB+C, DB+E, AE>B, CD+A, ECD} In each case, (i) Give all candidate keys (ii) Indicate the BCNF violation Give the minimal cover and decompose R into a collection of relations that are BCNF. Is it lossless? Does it preserve the dependencies?...
Help ASAP! 1. (10 pts) Given a relation schema R = (A, B, C, D, G,...
Help ASAP! 1. (10 pts) Given a relation schema R = (A, B, C, D, G, H) and a set of functional dependencies F = {D -> G, CD -> G, D -> C, H -> G} Find FC, a canonical cover of F. Please show all the steps to get your answer. 2. (30 pts) A Hollywood movie studio uses a relation called Movie to keep track of information about movie stars, what fee a star charges for...
consider the schema R-(A,B.C,D,E) and the following set F of functional dependencies holds on R ABC CD-E B- D E-A Problem 2. Suppose that we decompose the relation schema R into R, -(A, B, C) and R, (C, D,E). Show that this decomposition is not a lossless-join decomposition.
Find the decopmosition of R into R1(A, B, C), R2(B, C,D ) and
R3(C, D, E)
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CDAE, C-D, D-E} The decomposition of R into R1(A, B, C), R2(B, C, D) and RP(C, D, E) is (2 Points) Select one: Lossy and Not Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Dependency Preserving. Lossless and Dependency Preserving.
can you answer part e of the question
Q.31 Answer the following questions (a) Explain difference between lossy decomposition and lossless decomposition (b) If you write a SQL statement to inner join the following two tables based on Plocation value as inner join condition, is the result table lossy or lossless? (Explain why?) EMP LOCS P.K EMP PROJ1 Hours Pname Plocation Р.К. (c) Given a relation schema R ={SSN, Ename, Pnumber, Pname, Plocation, Hours) R is decomposed to R1, R2,...
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, D-E} The decomposition of Rinto R1(A, B, C), R2(B, C, D) and R3(C, D, E) is 2 Points) Select one: Lossless and Dependency Preserving. Lossy and Not Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Dependency Preserving.
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, D-E} The decomposition of Rinto R1(A, B, C), R2(B, C, D) and R3(C, D, E) is 2 Points) Select one: Lossless and Dependency Preserving. Lossy and Not Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Dependency Preserving.
Let R(A,B,C,D,E) be a relation with FDs F = {AB-CD, A-E, C-D, DE} The decomposition of R into R1(A, B, C), R2(B, C, D) and R3(C, D, E) is (2 Points) Select one: Lossy and Dependency Preserving. Lossless and Not Dependency Preserving. Lossy and Not Dependency Preserving. Lossless and Dependency Preserving.
Consider the schema R=(A, B, C, D, E) and let the following set F of functional dependencies hold for R: F= {A → BC, CD → E, B D } Problem 3 Suppose that the schema R=(A, B, C, D, E) is decomposed into R/ - (A, B, C) and R=(A, D, E). Show if this decomposition is a lossless decomposition with respect to the given set of functional dependencies F.
Given the following relation schemas and the sets of FD's: a- R(A,B,C,D) F={ABẠC,C7D, D´A, BC+C} b- R(A,B,C,D) F={BẠC, BD, AD>B} C- R(A,B,C,D) F={AB-C, DC+D, CD+A, AD+B} d- R(A,B,C,D) F={AB=C, C+D, D™B, DE} e- R(A, B, C, D, E) F= {AB+C, DB+E, AE>B, CD+A, ECD} In each case, (i) Give all candidate keys (ii) Indicate the BCNF violation Give the minimal cover and decompose R into a collection of relations that are BCNF. Is it lossless? Does it preserve the dependencies?...
Most questions answered within 3 hours.
-
How
can we prove that a flow is incompressible if the velocity field is
known?
asked 29 seconds from now -
It is sometimes argued that understanding people's existing
activities does not really help to design future...
asked 2 minutes ago -
what is the angular velocity of tje moon in its orbut ( orbit
period is 28)?
asked 4 minutes ago -
Time Off At Superior Software Service
As she hangs up the telephone, Joan Jackson realizes that...
asked 6 minutes ago -
Use the sample data and confidence level given below to complete
parts (a) through (d).
A...
asked 9 minutes ago -
1. Consider a risky portfolio. The end-of-year cash flow derived
from the portfolio will be either...
asked 10 minutes ago -
Find the critical value(s) for the specified Wilcoxon
signed-rank test.
Sample size = 10, two-tailed test,...
asked 43 minutes ago -
why don't arctic animals feet freeze in winter biology
question
asked 26 minutes ago -
Cellular respiration in eukaryotes has the same purpose as
fermentation in prokaryotes
True
False
asked 28 minutes ago -
A random sample of size n = 32 is taken from a
population with mean μ...
asked 39 minutes ago -
Define the term myogenic index and describe how it is measured
experimentally. What cellular process can...
asked 31 minutes ago -
5.) (a) How does go-back-by N ARQ work?
(b) What operations are required for CRC error...
asked 41 minutes ago