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Relational Databases
Chapter
!1
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Learning Objectives
" E#plain the importance and ad$antages o% databases& as 'ell as thedi%%erence bet'een database and %ile!based legacy systems.
" E#plain the di%%erence bet'een logical and physical $ie's o% adatabase.
" E#plain %undamental concepts o% database systems such as D()*&schemas& the data dictionary& and D()* languages.
" Describe 'hat a relational database is and ho' it organi+es data.
" Create a set o% 'ell!structured tables to properly store data in arelational database.
!2
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INTRODUCTION
" Relational databases underlie most modernintegrated ,-*s. /hey are the most popular type o% database used
%or transaction processing. -n this chapter& 'ell de%ine the concept o% a
database.
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What Is a Database?
" E%%iciently and centrally coordinates in%ormation %or arelated group o% %iles
" , %ile is a related group o% records
" , record is a related group o% %ields" , %ield is a speci%ic attribute o%
interest %or the entity record
!3
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FILE VS. DATAASES" Lets e#amine some basic principles about ho' data are
stored in computer systems. ,n entity is anything about 'hich the organi+ation 'ishes to
store data. ,t your college or uni$ersity& one entity 'ould be thestudent.
STUDENTS
Student ID Last Name First NamePhone
Number Birth Date
333-33-3333 Simpson Alice 333-3333 10/11/84
111-11-1111 Sanders Ned 444-4444 11/24/86
123-45-6789 Moore Artie 555-5555 04/20/85
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FILE VS. DATAASES -n%ormation about the attributes o% an entity e.g.&
the students -D number and birth date are stored in fields.
STUDENTS
Student ID Last Name First NamePhone
Number Birth Date
333-33-3333 Simpson Alice 333-3333 10/11/84
111-11-1111 Sanders Ned 444-4444 11/24/86
123-45-6789 Moore Artie 555-5555 04/20/85
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FILE VS. DATAASES ,ll the %ields containing data about one entity e.g.&
one student %orm a record . /he e#ample belo' sho's the record %or ,rtie )oore.
STUDENTS
Student ID Last Name First NamePhone
Number Birth Date
333-33-3333 Simpson Alice 333-3333 10/11/84
111-11-1111 Sanders Ned 444-4444 11/24/86
123-45-6789 Moore Artie 555-5555 04/20/85
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FILE VS. DATAASES
, set o% all related records %orms a file e.g.& thestudent %ile.
-% this uni$ersity only had three students and %i$e %ields%or each student& then the entire %ile 'ould be depicted
belo'.STUDENTS
Student ID Last Name First NamePhone
Number Birth Date
333-33-3333 Simpson Alice 333-3333 10/11/84
111-11-1111 Sanders Ned 444-4444 11/24/86
123-45-6789 Moore Artie 555-5555 04/20/85
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FILE VS. DATAASES , set o% interrelated& centrally coordinated %iles %orms
a database.
*tudent4ile
Class4ile
,d$isor4ile
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FILE VS. DATAASES
" /his proli%eration o% master%iles created problems 6%ten the same in%ormation 'as
stored in multiple master %iles.
)ade it more di%%icult toe%%ecti$ely integrate data andobtain an organi+ation!'ide $ie'o% the data.
,lso& the same in%ormation maynot ha$e been consistent bet'een
%iles. -% a student changed his phonenumber& it may ha$e beenupdated in one master %ile butnot another.
)aster 4ile 14act , 4act (4act C
)aster 4ile 24act , 4act D4act 4
)aster 4ile 14act , 4act (
4act 4
EnrollmentProgram
4inancial ,idProgram
7radesProgram
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FILE VS. DATAASES
" , database is a set o%inter!related& centrallycoordinated %iles.
Database4act , 4act (4act C 4act D4act E 4act 4
EnrollmentProgram
4inancial ,idProgram
7radesProgram
Database)anagement
*ystem
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FILE VS. DATAASES
" /he database approachtreats data as anorgani+ational resourcethat should be used byand managed %or theentire organi+ation& not 8ust a particulardepartment.
" , databasemanagement system
(DBMS) ser$es as theinter%ace bet'een thedatabase and the $ariousapplication programs.
Database4act , 4act (4act C 4act D4act E 4act 4
EnrollmentProgram
4inancial ,idProgram
7radesProgram
Database)anagement
*ystem
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FILE VS. DATAASES
" /he combination o%the database& theD()*& and the
application programsthat access thedatabase is re%erred toas the database
system.
Database4act , 4act (4act C 4act D4act E 4act 4
EnrollmentProgram
4inancial ,idProgram
7radesProgram
Database)anagement
*ystem
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FILE VS. DATAASES
" /he personresponsible %or thedatabase is thedatabaseadministrator .
" ,s technologyimpro$es& many largecompanies arede$eloping $ery largedatabases called datawarehouses.
Database4act , 4act (4act C 4act D4act E 4act 4
EnrollmentProgram
4inancial ,idProgram
7radesProgram
Database)anagement
*ystem
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I!"ORTANCE AND ADVANTA#ES OF DATAASE
S$STE!S" Database technology is e$ery'here.
)ost ne' ,-*s implement a database approach.
9irtually all main%rame computer sites usedatabase technology.
:se o% databases 'ith PCs is gro'ing also.
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I!"ORTANCE AND ADVANTA#ES OF DATAASE
S$STE!S" ,s accountants& you are li;ely to audit or 'or;
%or companies that use database technology tostore& process& and report accountingtransactions. )any accountants 'or; directly 'ith databases and
'ill enter& process& and
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I!"ORTANCE AND ADVANTA#ES OF DATAASE
S$STE!S" Database technology pro$ides the %ollo'ing bene%its to organi+ations Data integration
Data sharing Reporting %le#ibility
)inimal data redundancy and inconsistencies
Data independence
Central management o% data Cross!%unctional analysis
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I!"ORTANCE AND ADVANTA#ES OF DATAASE
S$STE!S" /he importance o% good data
(ad data leads to (ad decisions
Embarrassment
,ngry users
Data =arehousing -nstitute estimates that dirtydata costs >?00 billion per year in unnecessarypostage& mar;eting costs& and lost customer
credibility.
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DATAASE S$STE!S
" Logical and physical views of data -n %ile!oriented systems& programmers must ;no'
the physical location and layout o% records used by
a program. /hey must re%erence the location& length& and %ormat
o% e$ery %ield they utili+e.
=hen data is used %rom se$eral %iles& this process becomes more comple#.
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DATAASE S$STE!S
" Database systems o$ercome this problem byseparating the storage and use o% data elements. /'o separate $ie's o% the data are pro$ided
Logical $ie' Physical $ie'
Separating these views facilitatesapplication development, because
programmers can focus on coding the logicand not be concerned with storage details.
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Database
Logical View—User Logical View—User B
D()*
6perating
*ystem
The DB!S translatesusers" logical #iews
into instructions as to
which data should be
retrie#ed $rom the
database%
Enrollment b& 'lass*cholarship Distribution
4r.
5@*oph.
2@
Ar.
3B@
*r.
33@
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Database
Enrollment b& 'lass
Logical View—User Logical View—User B
D()*
6perating
*ystem
The o(erating s&stem
translates DB!S
re)uests into
instructions to
(h&sicall& retrie#e
data $rom #arious
dis*s%
*cholarship Distribution4r.
5@*oph.
2@
Ar.
3B@
*r.
33@
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DATAASE S$STE!S
" /he D()* handles the lin; bet'een the physicaland logical $ie's o% the data. ,llo's the user to access&
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DATAASE S$STE!S
" *eparating the logical and physical $ie's o% dataalso means users can change theirconceptuali+ations o% the data relationships 'ithout ma;ing changes in the physical storage.
" /he database administrator can also change thephysical storage o% the data 'ithout a%%ecting
users or application programs.
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DATAASE S$STE!S
" Schemas , schema describes the logical and physical
structures o% a database.
/here are three le$els o% schema. Conceptual level
• /he organi+ation!'ide $ie' o% the entire databasei.e.& the big picture.
• Lists all data elements and the relationships bet'een them.
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DATAASE S$STE!S" Schemas
, schema describes the logical and physicalstructures o% a database.
/here are three le$els o% schema. Conceptual le$el
External level
• , set o% indi$idual user $ie's o% portions o% thedatabase& i.e.& ho' each user sees the portion o%the system 'ith 'hich he interacts.
• /hese indi$idual $ie's are re%erred to assubschema.
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DATAASE S$STE!S
" Schemas , schema describes the logical and physical
structures o% a database.
/here are three le$els o% schema. Conceptual le$el
E#ternal le$el
Internal level
• , lo'!le$el $ie' o% the database.
• -t describes ho' the data are actuallystored and accessed including
– Record layouts – De%initions
– ,ddresses
– -nde#es
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Subschema++User Subschema++User B Subschema++User '
Enroll
CashReceipt
Classes *tudent
Student ,ecord 'lass ,ecord
Student No --c!aracter "9# $lass Name --c!aracter "9#
Student Name --c!aracter "26# %ept No --inte&er "4#' non-null' inde()item(
SA* Score --inte&er "2#' non-null' inde()item( $ourse No --inte&er "4#' non-null' inde()item(
!a((ing e-ternal+le#el #iews to conce(tual+le#el schema
!a((ing conce(tual+le#el items to internal+le#el descri(tions
*mith . . . , Aones . . . (
,rnold . . .D
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Subschema++User Subschema++User B Subschema++User '
Enroll
CashReceipt
Classes *tudent
Student ,ecord 'lass ,ecord
Student No --c!aracter "9# $lass Name --c!aracter "9#
Student Name --c!aracter "26# %ept No --inte&er "4#' non-null' inde()item(
SA* Score --inte&er "2#' non-null' inde()item( $ourse No --inte&er "4#' non-null' inde()item(
!a((ing e-ternal+le#el #iews to conce(tual+le#el schema
!a((ing conce(tual+le#el items to internal+le#el descri(tions
The
bidirectional
arrowsre(resent
ma((ings
between the
schema%
*mith . . . , Aones . . . (
,rnold . . .D
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DATAASE S$STE!S" /he D()* uses the mappings to translate a
re
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DATAASE S$STE!S
" ,ccountants are %re
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Database Users an% Designers
" Di%%erent users o% the database in%ormation areat an e#ternal le$el o% the database. /hese usersha$e logical views o% the data.
" ,t an internal le$el o% the database is thephysical view o% the data 'hich is ho' the datais actually physically stored in the system.
" Designers o% a database need to understand
users needs and the conceptual le$el o% theentire database as 'ell as the physical $ie'.
!5
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Database Design
" /o design a database& you need to ha$e aconceptual $ie' o% the entire database. /heconceptual $ie' illustrates the di%%erent %iles and
relationships bet'een the %iles.
" /he data dictionary is a blueprint o% thestructure o% the database and includes dataelements& %ield types& programs that use the dataelement& outputs& and so on.
!?
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DATAASE S$STE!S
" The data dictionary , ;ey component o% a D()* is the data
dictionary. Contains in%ormation about the data elements in the
database such as meaning& relationships to otherdata& origin& usage& and %ormat.
4or each data element& there is a corresponding
record in the data dictionary describing thatelement.
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DATAASE S$STE!S
" -n%ormation pro$ided %or each element includes , description or e#planation o% the element.
/he records in 'hich it is contained.
-ts source. /he length and type o% the %ield in 'hich it is stored.
/he programs in 'hich it is used.
/he outputs in 'hich it is contained.
/he authori+ed users o% the element. 6ther names %or the element.
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DATAASE S$STE!S• ,ccountants should participate in the
de$elopment o% the data dictionary because theyha$e a good understanding o% the data elements
in a business organi+ation& as 'ell as 'herethose elements originate and ho' they are used.
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DATAASE S$STE!S
" /he D()* usually maintains the datadictionary. -t is o%ten one o% the %irst applications o% a ne'ly
implemented database system. -nputs to the dictionary include
Records o% ne' or deleted data elements. Changes in names& descriptions& or uses o% e#isting elements.
6utputs include Reports that are use%ul to programmers& database designers&
and -* users in Designing and implementing the system. Documenting the system. Creating an audit trail.
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DATAASE S$STE!S
" !"S Languages E$ery D()* must pro$ide a means o%
per%orming the three basic %unctions o% Creating a database Changing a database Fuerying a database
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DATAASE S$STE!S" Creating a database
/he set o% commands used to create the databaseis ;no'n as data definition language (DDL).DDL is used to (uild the data dictionary -nitiali+e or create the database Describe the logical $ie's %or each indi$idual user or
programmer
*peci%y any limitations or constraints on securityimposed on database records or %ields
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DATAASE S$STE!S" Changing a database
/he set o% commands used to change the databaseis ;no'n as data manipulation language
(DML). D)L is used %or maintaining the dataincluding :pdating data
-nserting data
Deleting portions o% the database
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DATAASE S$STE!S" Fuerying a database
/he set o% commands used to
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DATAASE S$STE!S" Report =riter
)any D()* pac;ages also include a report writer &a language that simpli%ies the creation o% reports.
:sers typically speci%y =hat elements they 'ant printed
Go' the report should be %ormatted
/he report 'riter then *earches the database
E#tracts speci%ied data Prints them out according to speci%ied %ormat
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DATAASE S$STE!S
" :sers typically ha$e access to both DFL andreport 'riter.
" ,ccess to DDL and D)L are typically restricted
to employees 'ith administrati$e andprogramming responsibilities.
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RELATIONAL DATAASES
" , D()* is characteri+ed by the type o% logicaldata model on 'hich it is based. , data model is an abstract representation o%
the contents o% a database. )ost ne' D()*s are called relational
databases because they use the relational modelde$eloped by E. 4. Codd in 1HI0.
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RELATIONAL DATAASES
" /he relational data model representse$erything in the database as being stored in the%orms o% tables a;a& relations.
" /his model only describes ho' the data appear in the conceptual! and e#ternal!le$el schemas.
" /he data are physically stored according to thedescription in the internal!le$el schema.
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Each row is
called a tu(le.
which rh&mes
with /cou(le%0
E h
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Each row
contains data
about a s(eci$ic
occurrence o$
the t&(e o$ entit&in the table%
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Each column in
a table contains
in$ormation
about a s(eci$icattribute o$ the
entit&%
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(rimar& *e& is theattribute or combination
o$ attributes that
uni)uel& identi$ies a
s(eci$ic row in a table%
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In some tables. two or more attributes
ma& be 1oined to $orm the (rimar& *e&%
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DVIS2,S
d#isor No% Last Name First Name 2$$ice No%
1418 +o,ard len 420
1419 Melton Am. 316
1503 !an& i 202
1506 ado,si % 203
STUDENTS
Student ID Last NameFirst
Name Phone No%d#isor
No%
333-33-3333 Simpson Alice 333-3333 1418111-11-1111 Sanders Ned 444-4444 1418
123-45-6789 Moore Artie 555-5555 1503
$oreign *e& is an attribute in one table that is a (rimar& *e& in
another table%
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DVIS2,S
d#isor No% Last Name First Name 2$$ice No%
1418 +o,ard len 420
1419 Melton Am. 316
1503 !an& i 202
1506 ado,si % 203
Foreign *e&s are used to lin* tables together%
STUDENTS
Student ID Last NameFirst
Name Phone No%d#isor
No%
333-33-3333 Simpson Alice 333-3333 1418111-11-1111 Sanders Ned 444-4444 1418
123-45-6789 Moore Artie 555-5555 1503
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DVIS2,S
d#isor No% Last Name First Name 2$$ice No%
1418 +o,ard len 420
1419 Melton Am. 316
1503 !an& i 202
1506 ado,si % 203
2ther non+*e& attributes in each table store im(ortant
in$ormation about the entit&%
STUDENTS
Student ID Last NameFirst
Name Phone No%d#isor
No%
333-33-3333 Simpson Alice 333-3333 1418111-11-1111 Sanders Ned 444-4444 1418
123-45-6789 Moore Artie 555-5555 1503
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RELATIONAL DATAASES" ,lternati$es %or storing data
6ne possible alternate approach 'ould be to storeall data in one uni%orm table.
4or e#ample& instead o% separate tables %orstudents and classes& 'e could store all data in onetable and ha$e a separate line %or each student #class combination.
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Student IDLast
NameFirstName Phone No% 'ourse No% Section Da& Time
333-33-3333 Simpson Alice 333-3333 A$$*-3603 1 M 900 AM
333-33-3333 Simpson Alice 333-3333 N-3213 3 *! 1100 AM
333-33-3333 Simpson Alice 333-3333 MM*-3021 11 *! 1200 M
111-11-1111 Sanders Ned 444-4444 A$$*-3433 2 * 1000 AM
111-11-1111 Sanders Ned 444-4444 MM*-3021 5 800 AM
111-11-1111 Sanders Ned 444-4444 ANS-1422 7 900 AM
123-45-6789 Moore Artie 555-5555 A$$*-3433 2 * 1000 AM
123-45-6789 Moore Artie 555-5555 N-3213 3 *! 1100 AM
• :sing the suggested approach& a student ta;ing three classes 'ould
need three ro's in the table.
• -n the abo$e& simpli%ied e#ample& a number o% problems arise.
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Student IDLast
NameFirstName Phone No% 'ourse No% Section Da& Time
333-33-3333 Simpson Alice 333-3333 A$$*-3603 1 M 900 AM
333-33-3333 Simpson Alice 333-3333 N-3213 3 *! 1100 AM
333-33-3333 Simpson Alice 333-3333 MM*-3021 11 *! 1200 M
111-11-1111 Sanders Ned 444-4444 A$$*-3433 2 * 1000 AM
111-11-1111 Sanders Ned 444-4444 MM*-3021 5 800 AM
111-11-1111 Sanders Ned 444-4444 ANS-1422 7 900 AM
123-45-6789 Moore Artie 555-5555 A$$*-3433 2 * 1000 AM
123-45-6789 Moore Artie 555-5555 N-3213 3 *! 1100 AM
• *uppose ,lice *impson changes her phone number. Jou need to ma;e
the change in three places. -% you %ail to change it in all three places orchange it incorrectly in one place& then the records %or ,lice 'ill beinconsistent.
• /his problem is re%erred to as an update anomaly.
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Student IDLast
NameFirstName Phone No% 'ourse No% Section Da& Time
333-33-3333 Simpson Alice 333-3333 A$$*-3603 1 M 900 AM
333-33-3333 Simpson Alice 333-3333 N-3213 3 *! 1100 AM
333-33-3333 Simpson Alice 333-3333 MM*-3021 11 *! 1200 M
111-11-1111 Sanders Ned 444-4444 A$$*-3433 2 * 1000 AM
111-11-1111 Sanders Ned 444-4444 MM*-3021 5 800 AM
111-11-1111 Sanders Ned 444-4444 ANS-1422 7 900 AM
123-45-6789 Moore Artie 555-5555 A$$*-3433 2 * 1000 AM
123-45-6789 Moore Artie 555-5555 N-3213 3 *! 1100 AM
• =hat happens i% you ha$e a ne' student to add& but he hasnt signed up
%or any courses yetK
• 6r 'hat i% there is a ne' class to add& but there are no students enrolledin it yetK -n either case& the record 'ill be partially blan;.
• /his problem is re%erred to as an insert anomaly.
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Student IDLast
NameFirstName Phone No% 'ourse No% Section Da& Time
333-33-3333 Simpson Alice 333-3333 A$$*-3603 1 M 900 AM
333-33-3333 Simpson Alice 333-3333 N-3213 3 *! 1100 AM
333-33-3333 Simpson Alice 333-3333 MM*-3021 11 *! 1200 M
111-11-1111 Sanders Ned 444-4444 A$$*-3433 2 * 1000 AM
111-11-1111 Sanders Ned 444-4444 MM*-3021 5 800 AM
111-11-1111 Sanders Ned 444-4444 ANS-1422 7 900 AM
123-45-6789 Moore Artie 555-5555 A$$*-3433 2 * 1000 AM
123-45-6789 Moore Artie 555-5555 N-3213 3 *! 1100 AM
• -% ed 'ithdra's %rom all his classes and you eliminate all three o% his
ro's %rom the table& then you 'ill no longer ha$e a record o% ed. -% edis planning to ta;e classes ne#t semester& then you probably didntreally 'ant to delete all records o% him.
• /his problem is re%erred to as a delete anomaly.
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RELATIONAL DATAASES
" ,lternati$es %or storing data ,nother possible approach 'ould be to store each
student in one ro' o% the table and create multiple
columns to accommodate each class that he ista;ing.
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• /his approach is also %raught 'ith problems
– Go' many classes should you allo' in building the tableK
– /he abo$e table is
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• /he solution to the preceding problems is
to use a set o% tables in a relationaldatabase.
• Each entity is stored in a separate table&and separate tables or %oreign ;eys can beused to lin; the entities together.
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RELATIONAL DATAASES" !asic re#uirements of a relational database
E$ery column in a ro' must be single $alued. -n other 'ords& e$ery cell can ha$e one and only one $alue.
-n the student table& you couldnt ha$e an attributenamed Phone umber i% a student could ha$emultiple phone numbers.
/here might be an attribute named local phonenumber and an attribute named permanent phone
number. Jou could not ha$e an attribute named Class in the
student table& because a student could ta;e multipleclasses.
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RELATIONAL DATAASES
" !asic re#uirements of a relationaldatabase /he primary ;ey cannot be null.
/he primary ;ey uni
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• ote that 'ithin each table& there are noduplicate primary ;eys and no null primary;eys.
• Consistent 'ith the entity integrity rule.
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RELATIONAL DATAASES" !asic re#uirements of a relational
database , %oreign ;ey must either be null or correspond to
the $alue o% a primary ;ey in another table. /his rule is re%erred to as the referential
integrity rule.
/he rule is necessary because %oreign ;eys are usedto lin; ro's in one table to ro's in another table.
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DVIS2,S
d#isor No% Last Name First Name 2$$ice No%
1418 +o,ard len 420
1419 Melton Am. 316
1503 !an& i 202
1506 ado,si % 203
STUDENTS
Student ID Last NameFirst
Name Phone No%d#isor
No%
333-33-3333 Simpson Alice 333-3333 1418111-11-1111 Sanders Ned 444-4444 1418
123-45-6789 Moore Artie 555-5555 1503
d#isor No% is a $oreign *e& in the STUDENTS table% E#er&
incident o$ d#isor No% in the STUDENTS table either matches
an instance o$ the (rimar& *e& in the DVIS2,S table or is null%
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RELATIONAL DATAASES" !asic re#uirements of a relational
database ,ll non!;ey attributes in a table should describe a
characteristic o% the ob8ect identi%ied by theprimary ;ey. Could nationality be a non!;ey attribute in the
student tableK
Could adisor!s nationality be a non!;eyattribute in the student tableK
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RELATIONAL DATAASES
" /he preceding %our constraints produce a 'ell!structured normali+ed database in 'hich Data are consistent.
Redundancy is minimi+ed and controlled.
" -n a normali+ed database& attributes appearmultiple times only 'hen they %unction as%oreign ;eys.
" /he re%erential integrity rule ensures there 'ill be no update anomaly problem 'ith %oreign;eys.
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RELATIONAL DATAASES
" ,n important %eature is that data about $arious things o%interest entities are stored in separate tables. )a;es it easier to add ne' data to the system.
Jou add a ne' student by adding a ro' to the student
table. Jou add a ne' course by adding a ro' to the course table. )eans you can add a student e$en i% he hasnt signed up
%or any courses. ,nd you can add a class e$en i% no students are yet
enrolled in it.
)a;es it easy to a$oid the insert anomaly." *pace is also used more e%%iciently than in the other
schemes. /here should be no blan; ro's or attributes.
• ,dd a
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studenthere.
• Lea$es no
blan;spaces.
• ,dd a course here.• Lea$es no blan; spaces.
• =hen a particular student enrolls %or aparticular course& add that in%o here.
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RELATIONAL DATAASES" Deletion o% a class %or a student 'ould cause the
elimination o% one record in the student # classtable.
/he student still e#ists in the student table. /he class still e#ists in the class table.
,$oids the delete anomaly.
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• ed stille#ists inthe student
table.
•E$en i% ed 'as the only student inthe class& ,CC/!3?03 still e#ists in thecourse table.
• -% ed *anders drops ,CC/!3?03& remo$eeds class %rom this table.
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Re&ati'na& Data Tab&es
!10
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Re&ati'na& Data Tab&es
!11
Primary Meys
$oreign %ey Customer N is a 4oreign ;ey inthe *ales /able because it is a Primary ;ey that uni
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Wh( )ave a Set '* Re&ate% Tab&es?
" Data stored in one large table can be redundantand ine%%icient causing the %ollo'ing problems :pdate anomaly
-nsert anomaly
Delete anomaly
!12
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Re&ati'na& Database Design R+&es
" E$ery column in a ro' must be single $alued" Primary ;ey cannot be null empty also ;no'n as entity integrity
" -4 a %oreign ;ey is not null& it must ha$e a $alue that corresponds tothe $alue o% a primary ;ey in another table re%erential integrity
" ,ll other attributes in the table must describe characteristics o% the
ob8ect identi%ied by the primary ;ey
4ollo'ing these rules allo's databases to be normali+ed and sol$es theupdate& insert& and delete anomalies.
!13
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,e( Ter-s" Database
" Database management systemD()*
" Database system
" Database administrator D(,
" Data 'arehouse
" (usiness intelligence
" 6nline analytical processing6L,P
" Data mining
" Record layout
" Logical $ie'
" Physical $ie'
" *chema
" Conceptual!le$el schema
" E#ternal!le$el schema
" *ubschema" -nternal!le$el schema
" Data dictionary
" Data de%inition languageDDL
" Data manipulation languageD)L
" Data
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,e( Ter-s c'ntin+e%/" :pdate anomaly
" -nsert anomaly
" Delete anomaly
" Relational database
" Entity integrity rule
" Re%erential integrity rule
" ormali+ation
" *emantic data modeling