pert.12.normalization cont (tugas teori)

8/6/2019 PERT.12.Normalization Cont (Tugas Teori)

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Slide 11-2Elmasri and Navathe, Fundamentals of Database Systems, Fourth EditionRevised by IB & SAM, Fasilkom UI, 2005

Exercise Multiple Choices

Which of the following is known to be true from thefunctional dependency shown as (A, B) (C, D)?a. A is the determinant of Cb. A and B together are determined by C and D togetherc. A and B together determine D

d. C and D together determine Ae. A determines B

Which of the following is not a requirement for 1NF?a. cells must contain single values

b. all entries in a column must be of the same kindc. no two rows may be identicald. rows must be ordered by the value of the primary keye. the order of the columns is insignificant


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Further Normalization

The main reference of this preElmasri &Navathe, Fundamentalthedition,2004, Chapter 11Additional resources: presentDemurjian, Sr (http://www.engr.


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What are Possible Decompositions?

S#

S1

S2

S3S4

D1

D1

D2D3

DHead

John

John

Smith

Black

DName

G Information Based

R = ( U, F ) U = { S#, DName, DHead }

F = { S#o DName, DName o DHead }

G = { R1(S#, ), R2(DName, R3(DHead, )}G is Neither Lossless nor FD-Preserving


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S# DName

S1

S2

S3

S4

D1

D1D2

D3

S# DHead

S1

S2S3

S4

John

JohnSmith

Black

G Lossless Decomposition but

not Dependency-Preserving

DNameo DHead is lost inthe decomposition



G = { R1({S# ,DName}, {S#o DName}),R2({S#, DHead}, {S#o DHead})}

Gis Lossless but not FD-Preserving


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S# DName

S1

S2

S3

S4

D1

D1

D2D3

DName DHead

John

JohnD1

D1

D2D3

G Lossless & dependency-

preserving decomposition



= { R1({S# ,DName}, {S# o DName})R3({DName, DHead}, {Dname o DHead})}

G is both Lossless and FD-Preserving


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Slide 11-17Elmasri and Navathe, Fundamentals of Database Systems, Fourth EditionRevised by IB & SAM, Fasilkom UI, 2005BCNF

Eliminate the Partial Functional

Dependencies of Non-primeAttributes to Key Attributes

Eliminate the Transitive

Functional Dependencies ofNon-prime Attributes to KeyAttributes

Eliminate the Partial andTransitive FunctionalDependencies of Prime (Key)Attributes to Key

Lossless Decomposition

but not DependencyPreserving

Lossless Decomposition

and Dependency Preserving2NF

3NF

1NF

Summary of Normalization


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The Entire Normalization Picture1NF

2NF

3NF

BCNF

Eliminate Partial FDs of

Non-prime Attributes to Key

Eliminate Transitive FDs of Non-prime

Attributes to Key

Eliminate Partial and Transitive FDsof Prime Attributes to Key

4NF

Eliminate Non-trivial and Non-

functional Multi-Valued Dependencies

5NF

Eliminate Join Dependencies that are

Not Implied by Candidate Key

Wh t M lti V l d


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What are Multi-ValuedDependencies?

Focused on the Concept of Multi-Valued Dependencies

A MVD X oo Y Indicates that a Value of X Correspondsto Multiple Values of Y

Consider EMP with MVDs:

ENAME ooPNAME (E works on many Project)

ENAME oo DNAME (E has many Dependents)


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What is Fourth Normal Form (4NF)? A Relation Schema R is in Fourth Normal Form (4NF)

w.r.t Dependencies F (FD and MVD) if for every Non-Trivial MVD X oo Y in F+, X is a Superkey for R

MVD X oo Y in R is called trivial ifY is subset of X, or

X U Y = R Reconsider EMP with MVDs:

ENAME oo PNAME (E works on many P)ENAME oo DNAME (E has many Dependents)

ENAME is Not a Superkey of R since Need Triple ofENAME, PNAME, and DNAME to Distinguish

We need to Decompose EMP!


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Notes on FD

A functional dependency is trivial if it issatisfied by all instances of a relationE.g.

customer-name, loan-number o customer-name customer-name o customer-name

In general, D o Eis trivial ifE D


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Decomposition into 4NF

ENAMEooPNAME is Trivial MVD: EPNAMEqual to EMP_PROJECTS (samENAMEooDNAM


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Multivalued Dependencies and 4NF

Decomposing a relation state of EMP that is not in 4NF. (a) EMP relation with

additional tuples. (b) Two corresponding 4NF relations EMP_PROJECTS andEMP_DEPENDENTS.


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Other Normalizations

You can read by yourself


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Slide 11-27Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition

Exercise 10.33

Consider the following relation for published books: BOOK (Book_title, Authorname, Book_type, Listprice,

Author_affil, Publisher) Author_affil referes to the affiliation of the author. Suppose the

following dependencies exist: Book_title -> Publisher, Book_type Book_type -> Listprice Author_name -> Author-affil

(a) What normal form is the relation in? Explain your

answer. (b) Apply normalization until you cannot decompose the

relations further. State the reasons behind eachdecomposition.

pert.12.normalization cont (tugas teori)

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