Normal forms

Rushdi Shams, Dept of CSE, KUET 1
Database SystemsDatabase Systems
Normal FormsNormal Forms
Version 1.0Version 1.0

2Rushdi Shams, Dept of CSE, KUET
NormalizationNormalization
 ItIt avoids duplication of dataavoids duplication of data. Hence it is a. Hence it is a tool totool to
avoid redundancy of dataavoid redundancy of data..
 Theorists gave loads of “do this”, “do that” thing whenTheorists gave loads of “do this”, “do that” thing when
relational model was first invoked. One of those wererelational model was first invoked. One of those were
normal forms. Applying those theories on databases arenormal forms. Applying those theories on databases are
called normalizatoin.called normalizatoin.
 But the fact is,But the fact is, in commercial environment, loads ofin commercial environment, loads of
works are done by not maintaining theworks are done by not maintaining the
normalization theories 100%!normalization theories 100%!

Why Normalization?Why Normalization?

Why Normalization? (continued)Why Normalization? (continued)
 What if we want to delete the student no 34668?What if we want to delete the student no 34668?
Alas! We will lose information about DEDUCTIVEAlas! We will lose information about DEDUCTIVE
DATABASE, its lecturer name and many more!DATABASE, its lecturer name and many more!
 What if we want to update the lecturer to NICKWhat if we want to update the lecturer to NICK
WHITTAKER? We will have to put staff name as wellWHITTAKER? We will have to put staff name as well
as staff no for that!as staff no for that!
 What if we want to insert a new student with numberWhat if we want to insert a new student with number
38989? We cannot insert any student who does not38989? We cannot insert any student who does not
have any assessment criteria!have any assessment criteria!

AnomaliesAnomalies
 An anomaly is a bad thing. Because it tends theAn anomaly is a bad thing. Because it tends the
data in a database LOGICALLY getdata in a database LOGICALLY get
corrupted!corrupted!
 There are mainly 3 types of anomaliesThere are mainly 3 types of anomalies
1.1. Insert anomalyInsert anomaly
2.2. Delete anomalyDelete anomaly
3.3. Update anomalyUpdate anomaly
The reason why I switched to discuss aboutThe reason why I switched to discuss about
anomaly- you will understand later!anomaly- you will understand later!

Insert AnomalyInsert Anomaly
 It is caused when an insertion takes place in aIt is caused when an insertion takes place in a
child table, where there is no record in thechild table, where there is no record in the
parent table!parent table!

Insert Anomaly (continued)Insert Anomaly (continued)
 What if you try to insertWhat if you try to insert
a book of J K Rawlingsa book of J K Rawlings
into the table left withoutinto the table left without
putting her name into theputting her name into the
table below?table below?

Delete AnomalyDelete Anomaly
 Caused when a data in the parent table is deletedCaused when a data in the parent table is deleted
before deleting all the related data from its childbefore deleting all the related data from its child
(ren) table(s).(ren) table(s).
 Well, if you prefer a cascaded deletion, no oneWell, if you prefer a cascaded deletion, no one
would mind!would mind!

Delete Anomaly (continued)Delete Anomaly (continued)
 Before deleting the dataBefore deleting the data
from the table below, iffrom the table below, if
you delete data fromyou delete data from
table in right, what dotable in right, what do
you think it is gonnayou think it is gonna
happen?happen?

Update AnomalyUpdate Anomaly
 It is kind of like delete anomaly. Both the parentIt is kind of like delete anomaly. Both the parent
table and child(ren) table(s) should get updatedtable and child(ren) table(s) should get updated
concurrently!concurrently!

More JargonsMore Jargons
 Well, before starting with normalizations, youWell, before starting with normalizations, you
must need to know some jargons. You alreadymust need to know some jargons. You already
are aware of anomalies. Let’s get into someare aware of anomalies. Let’s get into some
more!more!

Functional DependencyFunctional Dependency
 Y is functionally dependent on X if the values ofY is functionally dependent on X if the values of
Y are determined by the values of X.Y are determined by the values of X.
 Y=X+1. In this case, Y is functionallyY=X+1. In this case, Y is functionally
dependent on Xdependent on X
 y=f(x). In this generic case, y is functionallyy=f(x). In this generic case, y is functionally
dependent on x as well.dependent on x as well.

Functional Dependency (continued)Functional Dependency (continued)
 In this case, CURRENCY is functionallyIn this case, CURRENCY is functionally
dependent on FXCODEdependent on FXCODE

DeterminantDeterminant
 If X determines the values of Y, then X will beIf X determines the values of Y, then X will be
called the determinant of Ycalled the determinant of Y
 Y=X+1. In this case, X is determinant of Y.Y=X+1. In this case, X is determinant of Y.
 y=f(x). In this case, x is determinant of y as well.y=f(x). In this case, x is determinant of y as well.

Determinant (continued)Determinant (continued)
 In this case, FXCODE is determinant ofIn this case, FXCODE is determinant of
CURRENCY.CURRENCY.

Transitive DependencyTransitive Dependency
 If the value of Z is determined by Y and theIf the value of Z is determined by Y and the
value of Y is determined by X, then there is avalue of Y is determined by X, then there is a
transitive dependency between X and Z.transitive dependency between X and Z.
 This dependency thus states the indirectThis dependency thus states the indirect
dependency.dependency.
BackBack

Transitive Dependency (continued)Transitive Dependency (continued)
 In this case, RATE is dependent onIn this case, RATE is dependent on
CURRENCY. CURRENCY is dependent onCURRENCY. CURRENCY is dependent on
COUNTRY. So, RATE is transitively dependentCOUNTRY. So, RATE is transitively dependent
on COUNTRY.on COUNTRY.

Candidate keyCandidate key
 It is theIt is the minimal setminimal set of super key.of super key.
 Say, from this example, you only can have super keysSay, from this example, you only can have super keys
as followings (though you may have otheras followings (though you may have other
combinations, but just shorten that this time)-combinations, but just shorten that this time)-
{roll, name}, {roll, name, dept}, {roll, name, year,{roll, name}, {roll, name, dept}, {roll, name, year,
semester}semester}
In this case, the candidate key is {roll, name}!In this case, the candidate key is {roll, name}!
RollRoll NameName DeptDept YearYear SemestSemest
erer

Full Functional DependencyFull Functional Dependency
 If X determines Y but X with combination of ZIf X determines Y but X with combination of Z
does not determine Y- then, there is a fulldoes not determine Y- then, there is a full
functional dependency between X and Y.functional dependency between X and Y.
 So, X cannot be a composite key.So, X cannot be a composite key.
Nb. If you make a key with 2 or more columns,Nb. If you make a key with 2 or more columns,
then that is called a composite key.then that is called a composite key.

Full Functional DependencyFull Functional Dependency
(continued)(continued)
 In this case,In this case,
POPULATION dependsPOPULATION depends
on COUNTRY not onon COUNTRY not on
the combination ofthe combination of
RATE andRATE and
COUNTRY. So,COUNTRY. So,
POPULATION is fullyPOPULATION is fully
functional dependent onfunctional dependent on
COUNTRY and also youCOUNTRY and also you
can say that,can say that,
POPULATION is notPOPULATION is not
fully functionalfully functional
dependent on RATE anddependent on RATE and
COUNTRY!COUNTRY!

11stst
Normal Form: 1NFNormal Form: 1NF
 Academic Definitions:Academic Definitions:
1. Eliminate repeating groups such that all
records in all tables can be identified uniquely
by a primary key in each table. In other words,
all fields other than the primary key must
depend on the primary key.
2. A relation is in first normal form if and only if
every non-key attribute is functionally
dependent upon the primary key

1 NF (continued)1 NF (continued)
3. A relation is in first normal form if the
domains on which its attributes are defined are
scalar
BackBack

 Easy Definition:Easy Definition:
1 NF is a process of removing repeating groups1 NF is a process of removing repeating groups
from a table by creating a new tablefrom a table by creating a new table
They are linked by a one to many relationshipThey are linked by a one to many relationship
Create primary keys on both tablesCreate primary keys on both tables
The child table will have a composite primaryThe child table will have a composite primary
key (one of its own, other is its foreign key fromkey (one of its own, other is its foreign key from
its parent table)its parent table)

What does 1 NF do?What does 1 NF do?
 Academic Way:Academic Way:
 Eliminates repeating groupsEliminates repeating groups
 Defines primary keysDefines primary keys
 No duplicate entry allowedNo duplicate entry allowed
 All fields other than primary key depend on primaryAll fields other than primary key depend on primary
keykey
 All columns must contain a single value (seeAll columns must contain a single value (see
Definition 3Definition 3))
 All values in a column must have the same data typeAll values in a column must have the same data type
 Create a table to move repeating data from the currentCreate a table to move repeating data from the current
tabletable

Not Scalar- Not 1 NFNot Scalar- Not 1 NF

Repeating Groups- Not 1 NFRepeating Groups- Not 1 NF

0 NF to 1 NF0 NF to 1 NF
 Remove repeatingRemove repeating
groups. Split table intogroups. Split table into
tables with one to manytables with one to many
relationship.relationship.

0 NF to 1 NF (continued)0 NF to 1 NF (continued)
 Creating primary key onCreating primary key on
parent table andparent table and
composite primary keycomposite primary key
on child table (where iton child table (where it
has a foreign keyhas a foreign key
referenced to parentreferenced to parent
table)table)

Our 1 NFOur 1 NF

Can you do it?Can you do it?

Yes! You Can!!Yes! You Can!!

Second Normal Form- 2 NFSecond Normal Form- 2 NF
 Academic Definition:Academic Definition:
1. A relation is in second normal form if and only
if it is in first normal form and every non-key
attribute is fully functionally dependent on the
primary key
2.2. A relation is in second normal form ifA relation is in second normal form if it is init is in
first normal formfirst normal form and, in addition,and, in addition, all itsall its
attributes are dependent on the entireattributes are dependent on the entire
candidate keycandidate key

What does 2 NF do?What does 2 NF do?
 The table is in 1 NFThe table is in 1 NF
 All non-key values must be functionally dependent on
the primary key. In other words, non-key fields not
dependent on the primary key are not allowed.
 Partial dependencies must be removed. A partial
dependency is a special type of functional dependency
that exists when a field is dependant on a part of a
composite primary key.
 Create a table with partially dependent part of the
primary key and its dependents.

Which is not 2 NF?Which is not 2 NF?
Solution!Solution!

1 NF to 2 NF1 NF to 2 NF

Separating TablesSeparating Tables

Providing Many to One RelationProviding Many to One Relation

Providing One to Many RelationshipProviding One to Many Relationship

Can You Do It?Can You Do It?

Remember Me? I was not 2 NF!!Remember Me? I was not 2 NF!!
See Me!See Me!

33rdrd
Normal Form- 3 NFNormal Form- 3 NF
 The table must be in 2 NFThe table must be in 2 NF
 Eliminate transitive dependency (Eliminate transitive dependency (
see Transitive Dependencysee Transitive Dependency))
 Create a new table to contain any separatedCreate a new table to contain any separated
columnscolumns

3 NF3 NF
 Easy Way:Easy Way:
 Meet the requirements by 1 NF and 2 NFMeet the requirements by 1 NF and 2 NF
 Remove columns that are not fully dependentRemove columns that are not fully dependent
on the primary keyon the primary key

3 NF (case study)3 NF (case study)
 Imagine we have a table that contains theImagine we have a table that contains the
following columns-following columns-
1.1. Order numberOrder number
2.2. Customer numberCustomer number
3.3. Unit priceUnit price
4.4. QuantityQuantity
5.5. TotalTotal

3 NF (case study): Checking if it is in3 NF (case study): Checking if it is in
1 NF1 NF
5.5. TotalTotal
 Are there duplicate columns? No!Are there duplicate columns? No!
 Do we have a primary key? Yes, the order number!Do we have a primary key? Yes, the order number!
 Fine, it is in 1 NF then!!Fine, it is in 1 NF then!!

2 NF2 NF
5.5. TotalTotal
 Are there any static of data that apply toAre there any static of data that apply to
multiple rows? No!multiple rows? No!
 Fine, we are in 2 NF then!!Fine, we are in 2 NF then!!

3 NF3 NF
5.5. TotalTotal
 Are all of the columns fully depend on theAre all of the columns fully depend on the
primary key (order number)?primary key (order number)?

 The customer number varies with the order numberThe customer number varies with the order number
and it doesn't appear to depend upon any of the otherand it doesn't appear to depend upon any of the other
fieldsfields
 What about the unit price? This field could beWhat about the unit price? This field could be
dependent upon the customer number in a situationdependent upon the customer number in a situation
where we charged each customer a set price. However,where we charged each customer a set price. However,
looking at the data above, it appears we sometimeslooking at the data above, it appears we sometimes
charge the same customer different prices. Therefore,charge the same customer different prices. Therefore,
the unit price is fully dependent upon the order numberthe unit price is fully dependent upon the order number

 The quantity of items also varies from order toThe quantity of items also varies from order to
order, so we're OK there.order, so we're OK there.
 What about the total? It looks like we might beWhat about the total? It looks like we might be
in trouble here. The total can be derived byin trouble here. The total can be derived by
multiplying the unit price by the quantity,multiplying the unit price by the quantity,
therefore it's not fully dependent upon thetherefore it's not fully dependent upon the
primary key. We must remove it from the tableprimary key. We must remove it from the table
to comply with the third normal form.to comply with the third normal form.

3 NF (case study): Making it a 3 NF3 NF (case study): Making it a 3 NF
 Now, the table is in 3 NF. What about total?Now, the table is in 3 NF. What about total?
Well, there is no need to put it on a separateWell, there is no need to put it on a separate
table! You can make a select command to grabtable! You can make a select command to grab
the total by multiplying unit price withthe total by multiplying unit price with
quantity- can’t you?quantity- can’t you?

3 NF3 NF
 Did you see theDid you see the
irrelevant columns in theirrelevant columns in the
2 tables?2 tables?
 You need to separateYou need to separate
them!them!

 Eliminated the irrelevantEliminated the irrelevant
columns and makingcolumns and making
them a separate table.them a separate table.

 Can you see theCan you see the
irrelevant column here?irrelevant column here?
them to make it a 3 NF!them to make it a 3 NF!

 Did you see the columnDid you see the column
that does not depend onthat does not depend on
the primary key?the primary key?
that column from thethat column from the
table to make it 3 NFtable to make it 3 NF

Can you do it?Can you do it?

Be warned!Be warned!
 3 NF is said to be the most crucial and most3 NF is said to be the most crucial and most
ambiguous, most complex part of normalization!ambiguous, most complex part of normalization!

Bad thing of too much normalizationBad thing of too much normalization
 Did you take a look at the number of tableDid you take a look at the number of table
increased from 0 NF to 3 NF? If it is a bigincreased from 0 NF to 3 NF? If it is a big
enterprise database, then can you imagine howenterprise database, then can you imagine how
far this can go?far this can go?
 Too many tables lead us to too many joinsToo many tables lead us to too many joins
 Joins are one of the complex codings and timeJoins are one of the complex codings and time
consuming subtle entities in database systemsconsuming subtle entities in database systems
 So, try to normalize, but don’t normalize in aSo, try to normalize, but don’t normalize in a
way that you have 1000 tables!way that you have 1000 tables!

Beyond 3 NFBeyond 3 NF
 Most software development firms dealing withMost software development firms dealing with
database systems do not go beyond 3 NF anddatabase systems do not go beyond 3 NF and
many of them even try not to reach 3 NF!!many of them even try not to reach 3 NF!!

Boyce Codd Normal Form (BCNF)Boyce Codd Normal Form (BCNF)
 It is a variation of 3 NFIt is a variation of 3 NF
 In a 3NF table, all attributes are dependent on a key, aIn a 3NF table, all attributes are dependent on a key, a
whole key and nothing but a keywhole key and nothing but a key
 A table is said to be in BCNF if and only if it is in 3NFA table is said to be in BCNF if and only if it is in 3NF
and every non-trivial, left-irreducible functionaland every non-trivial, left-irreducible functional
dependency has a candidate key as its determinantdependency has a candidate key as its determinant
 In more informal terms, a table is in BCNF if it is inIn more informal terms, a table is in BCNF if it is in
3NF and the only determinants are the candidate keys3NF and the only determinants are the candidate keys

BCNF (continued)BCNF (continued)

 Primary key is product category and productPrimary key is product category and product
subcategorysubcategory
 The table is in 3NF, for each of its non-key attributes isThe table is in 3NF, for each of its non-key attributes is
non-transitively dependent on the full key (Productnon-transitively dependent on the full key (Product
Category, Product Subcategory).Category, Product Subcategory).

 Yet the table has redundant data. Look at column 1,Yet the table has redundant data. Look at column 1,
column 3 and column 4 for the last 4 rows!column 3 and column 4 for the last 4 rows!

 Indeed, Range Code is dictated by the combination of ProductIndeed, Range Code is dictated by the combination of Product
Category and Stock CategoryCategory and Stock Category
 Is stock category a candidate key? NO! Then it is not in BCNF!!Is stock category a candidate key? NO! Then it is not in BCNF!!

 The point about BCNF is that a candidate key is, by
definition, a unique key, and thus a potential primary
key.
 If a table contains more than one candidate key
(primary key), it has a problem according to BCNF. I
disagree!
 BCNF divides a table up into multiple tables to ensure
that no single table has more than one potential primary
key
 BCNF prohibits a table from having two possible
primary keys.

Anomaly problemAnomaly problem
 In this table, say, studentNo and Area is primary keyIn this table, say, studentNo and Area is primary key

 What if 123456 wants to change her subject toWhat if 123456 wants to change her subject to
information systems? We will lose the data-information systems? We will lose the data-
who is taking the course computer science?who is taking the course computer science?
 This is update anomalyThis is update anomaly

 What if staff 250 also will take computer science? IfWhat if staff 250 also will take computer science? If
there is no student enrolled in that subject, then wethere is no student enrolled in that subject, then we
cannot insert that information in this table!!cannot insert that information in this table!!
 This is insert anomalyThis is insert anomaly

 What if 123456 wants to withdraw from the courseWhat if 123456 wants to withdraw from the course
Software Engineering? We will lose the data-Software Engineering? We will lose the data-
Who will take the course Software Engineering!!Who will take the course Software Engineering!!
 This is delete anomalyThis is delete anomaly

Why anomaly?Why anomaly?
 The anomalies occurred because, there are twoThe anomalies occurred because, there are two
overlapping candidate keys- student number andoverlapping candidate keys- student number and
area!area!

Normalizing to BCNFNormalizing to BCNF
 Suppose a relation R is not inSuppose a relation R is not in BCNFBCNF. Then there must be some. Then there must be some
functional dependency X → A where X is not a superkey.functional dependency X → A where X is not a superkey.
 In this case, the relation can be decomposed into the twoIn this case, the relation can be decomposed into the two
relationsrelations
1.1. R1= R − AR1= R − A
2.2. R2= XAR2= XA
 where R − A simply means dropping the attribute A from thewhere R − A simply means dropping the attribute A from the
schema and XA is the relation whose attributes are those in Xschema and XA is the relation whose attributes are those in X
together with Atogether with A
 Then examine the new tables if you can apply 1 and 2 on themThen examine the new tables if you can apply 1 and 2 on them
again!again!
 When you cannot apply 1 and 2 on them, then it’s in BCNF!!When you cannot apply 1 and 2 on them, then it’s in BCNF!!

BCNF ExampleBCNF Example
 Product category+stock category determines range code.Product category+stock category determines range code.
 So, make two tables.So, make two tables.
1.1. Product category, product subcategory, stock category, rangeProduct category, product subcategory, stock category, range
subcodesubcode
2.2. Product category, stock category, range codeProduct category, stock category, range code

BCNF example (continued)BCNF example (continued)

 Now, observe this new table. In it, the range subcodeNow, observe this new table. In it, the range subcode
depends on stock category and product subcategory.depends on stock category and product subcategory.
So, make two tables.So, make two tables.
1.1. Product category, product subcategory, stock categoryProduct category, product subcategory, stock category
2.2. Product subcategory, stock category, range subcodeProduct subcategory, stock category, range subcode

Our tables in BCNFOur tables in BCNF

Fourth Normal Form (4 NF)Fourth Normal Form (4 NF)
 A table must be in 3 NF or BCNF with 3 NFA table must be in 3 NF or BCNF with 3 NF
 Multi-valued dependencies must be transformed into functional
dependencies. This implies that one value and not multiple
values are dependent on a primary key.
 Eliminate multiple sets of multiple valued or multi-valued
dependencies, sometimes described as non-trivial multi-valued
dependencies.
 NF and has no multiple sets of multi-valued dependencies. In
other words, 4NF states that no entity can have more than a
single one-to-many relationship within an entity if the one-to-
many attributes are independent of each other.

4 NF Example4 NF Example
 In this table, there are 3In this table, there are 3
columns. Employee, skillcolumns. Employee, skill
and skilllanguageand skilllanguage
 Employee is the primaryEmployee is the primary
keykey
 The table is in BCNFThe table is in BCNF
with 3NFwith 3NF

 The record for employeeThe record for employee
number 0122443 can benumber 0122443 can be
written also in the form-written also in the form-
0122443: Typing,0122443: Typing,
Dictation: English,Dictation: English,
French in the formFrench in the form
employee: skill:employee: skill:
skilllanguageskilllanguage

 So, the multivaluedSo, the multivalued
dependency is on skilldependency is on skill
column and skilllanguagecolumn and skilllanguage
column!column!
 To make it in 4 NF, youTo make it in 4 NF, you
will have to simply splitwill have to simply split
them into separate table,them into separate table,
nothing else!!nothing else!!

Solving one, creates anotherSolving one, creates another
problem!problem!
 Can you say, what is the problem still with theCan you say, what is the problem still with the
tables?tables?
 There are still 2 entries for the same employee!!There are still 2 entries for the same employee!!

Fifth Normal Form (5 NF)Fifth Normal Form (5 NF)
 Personally, I really hate this form!!Personally, I really hate this form!!
 The table must have to be in 4 NF (same oldThe table must have to be in 4 NF (same old
dialogue!)dialogue!)
 The table should not contain any cyclicThe table should not contain any cyclic
dependency!dependency!
 Cyclic dependency is like say your table has 3Cyclic dependency is like say your table has 3
columns. Column 1 depends on 2, 2 on 3 and 3columns. Column 1 depends on 2, 2 on 3 and 3
on 1!!on 1!!
 Also known as PJNF (Projection Normal Form)Also known as PJNF (Projection Normal Form)

 Try begin with creating a table EmployeesTry begin with creating a table Employees
 All the 3 columns are primary key (kind of weird, isn’tAll the 3 columns are primary key (kind of weird, isn’t
it?? We can call it composite primary key)it?? We can call it composite primary key)

 Let’s insert some data in Employees table then.Let’s insert some data in Employees table then.

 Employees table now look like this!Employees table now look like this!
 There is no multivalued dependency, so, the table is inThere is no multivalued dependency, so, the table is in
4 NF (of course also in 1-2-3-BC NF!!)4 NF (of course also in 1-2-3-BC NF!!)

 Now, let’s play with the basic table Employees. We willNow, let’s play with the basic table Employees. We will
split the table into three tables. WHY? I will say yousplit the table into three tables. WHY? I will say you
later.later.
 We are making three tables- project_employee,We are making three tables- project_employee,
project_manager, manager_employeeproject_manager, manager_employee

Detail of project_employeeDetail of project_employee

Detail of project_managerDetail of project_manager

Detail of manager_employeeDetail of manager_employee

The Fun!The Fun!
 Now, we will query the initial table Employees! It will show usNow, we will query the initial table Employees! It will show us
the whole tablethe whole table

The Fun Continues!The Fun Continues!
 Now, we will join the three new tables and will get theNow, we will join the three new tables and will get the
same answer!!same answer!!

So, what is the fun for?So, what is the fun for?
 The fun is, if you have a table in 4 NF but withThe fun is, if you have a table in 4 NF but with
cyclic dependency, if you can split it into xcyclic dependency, if you can split it into x
number of tables and then while joining those xnumber of tables and then while joining those x
number of tables, it will give you back the initialnumber of tables, it will give you back the initial
table, you then made it 5 NF while splitting!table, you then made it 5 NF while splitting!
 Phew!!Phew!!

Domain Key Normal Form (DKNF)Domain Key Normal Form (DKNF)
 Please god, help us! There are loads of normalPlease god, help us! There are loads of normal
forms! I cannot go beyond that! Well, folks, thisforms! I cannot go beyond that! Well, folks, this
one is the last- I promise!!one is the last- I promise!!
 Domain/key normal form (DKNF) is a normalDomain/key normal form (DKNF) is a normal
used in database normalization which requiresused in database normalization which requires
that the database contains no constraints otherthat the database contains no constraints other
than domain constraints and key constraints.than domain constraints and key constraints.

DKNF (continued)DKNF (continued)
 This table violates the rules for being DKNFThis table violates the rules for being DKNF
 If Wealthy person type is Eccentric Millionaire/ evil millionaire,If Wealthy person type is Eccentric Millionaire/ evil millionaire,
then the Net Worth in Dollars must be 1,000,000 to 999,999,999then the Net Worth in Dollars must be 1,000,000 to 999,999,999
inclusive and if that is Evil Billionaire/ Eccentric Billionaire, theninclusive and if that is Evil Billionaire/ Eccentric Billionaire, then
it should be 1,000,000,000 or higher.it should be 1,000,000,000 or higher.

So, what to do?So, what to do?
 Nothing serious, the violation on domain can be solvedNothing serious, the violation on domain can be solved
easily by changing the domain of Wealthy Person Typeeasily by changing the domain of Wealthy Person Type
to Eccentric and Evil- forget about Millionaire andto Eccentric and Evil- forget about Millionaire and
Billionaire!!Billionaire!!
 It is then in DKNF!!It is then in DKNF!!

The Flow chartThe Flow chart
 Say, you are given a table in 0 NF. Do theSay, you are given a table in 0 NF. Do the
followings one by one-followings one by one-
1.1. Are there duplicate rows? Find the answer NoAre there duplicate rows? Find the answer No
2.2. Is there primary key? Find the answer yes (thenIs there primary key? Find the answer yes (then
you finished making it in 1 NF)you finished making it in 1 NF)
3.3. Are all the non-key columns functionallyAre all the non-key columns functionally
depend on primary key? Find the answer yesdepend on primary key? Find the answer yes
(then you finished making it 2 NF)(then you finished making it 2 NF)

The Flow Chart (continued)The Flow Chart (continued)
4.4. Are all the columns that are non key depending fullyAre all the columns that are non key depending fully
functionally upon the primary key? Find the answerfunctionally upon the primary key? Find the answer
yes (then you made it into 3 NF)yes (then you made it into 3 NF)
5.5. Are all the determinants candidate key of the table?Are all the determinants candidate key of the table?
Find the answer yes (then you made it into BCNF)Find the answer yes (then you made it into BCNF)
6.6. Are there multivalued dependency? Find the answerAre there multivalued dependency? Find the answer
no (then you made it into 4 NF)no (then you made it into 4 NF)
7.7. Are there any cyclic dependency? Find the answer noAre there any cyclic dependency? Find the answer no
(then you made it into 5 NF)(then you made it into 5 NF)
8.8. Are there any violation to domain constraints? FindAre there any violation to domain constraints? Find
the answer no (then you made it into DKNF)the answer no (then you made it into DKNF)

ReferencesReferences
 Designing Effective Database Systems byDesigning Effective Database Systems by
Rebecca M. Riordan, Addison WesleyRebecca M. Riordan, Addison Wesley
Professional, 2005Professional, 2005
 Database Systems by Paul Beynon-Devies,Database Systems by Paul Beynon-Devies,
Palgrave Macmillan, 2004Palgrave Macmillan, 2004
 www.wikipedia.orgwww.wikipedia.org
 Beginning Database Design by GavinBeginning Database Design by Gavin
Powell, Wrox Publications, 2005Powell, Wrox Publications, 2005

References (continued)References (continued)
 www.techtarget.comwww.techtarget.com
 http://http://databases.about.comdatabases.about.com
 Databases –Normalization by GordonDatabases –Normalization by Gordon
Royle, Department of Computer Science &Royle, Department of Computer Science &
Software Engineering University ofSoftware Engineering University of
Western AustraliaWestern Australia
 Database Management Systems by Prof.Database Management Systems by Prof.
Holowczak, Zicklin School of Business,Holowczak, Zicklin School of Business,
Baruch College, City University of NewBaruch College, City University of New
YorkYork

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