Matakuliah : F0174 / Audit Laporan Keuangan Berbasis
Komputer
Tahun
: 2008
Infrastruktur dalam Sistem Informasi Akuntansi dan
Database
Pertemuan 05-06
Infrastruktur Sistem Informasi Akuntansi
3
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• Four fundamentalobjectives to manage data:
– Sharability:
• Different stakeholders in organization should be permitted to access
and use the same data.
– Availability
• If data were to be shared, different stakeholders should be able to
access and use the data whenever they needed it.
– Evolvability
• Facilities had to exist that allowed data and its definition to be
modified easily in response to changingstakeholder needs.
– Integrity
• If data were to be shared among multiple stakeholders, its
authenticity, accuracy, and completenees had to preserved
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Konsep Digitalisasi Data
5
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MEMAHAMI BAGAIMANA KOMPUTER MENYAJIKAN DATA
• PENGKODEAN
– ASCII (American National Standard Code for information
Interchange)
format yang biasanya dijumpai pada IBM Mainframe
Komputer dan Mid Range Komputer
– EBCDIC (Extended Binary Coded Decimal Interchange
Code)
Format yang dijumpai pada hampir semua jenis komputer
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1
HIERARKI DATA DIGITAL (BINARY DIGIT)
DIGITAL
0
ANALOG
BIT
BYTE
1
8
UNICODE=16BIT=>65000CRKTR
WORD
DATABASE
RECORD
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DATA FILE
Representing Pictures, Time
•
Pictures
– Pixel : Ukuran ketajaman/detail jumlah cell dalam tiap inchi
Time
– Millisecond = 1/1000 seconds
– Microsenond = 1/1,000,000
– Nanosecond = 1/1,000,000,000
– Picosencond = 1/1,000,000,000,000
•
Representing Size of Bytes
•
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Size is measured by the number of bytes
– KB
-Kilobyte = 1,000 bytes (actually 1024)
– MB
-Megabyte = 1,000 kilobytes = 106 bytes
– GB
-Gigabyte = 109 bytes
– TB
-Terabyte = 1012 bytes
– PB
-Petabyte = 1015 bytes
– Exabyte - = 1018 bytes
Konsep Data Base
9
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File Systems
program 1
data description 1
File 1
program 2
data description 2
File 2
program 3
data description 3
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File 3
Database Management
Application
program 1
(with data
semantics)
Application
program 2
(with data
semantics)
Application
program 3
(with data
semantics)
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DBMS
description
manipulation
control
database
Motivation
Database
Technology
Computer
Networks
integration
distribution
Distributed
Database
Systems
integration
integration ≠ centralization
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Distributed Computing
• A concept in search of a definition and a name.
• A number of autonomous processing elements (not
necessarily homogeneous) that are interconnected
by a computer network and that cooperate in
performing their assigned tasks.
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Distributed Computing
• Synonymous terms
–
–
–
–
–
–
distributed function
distributed data processing
multiprocessors/multicomputers
satellite processing
backend processing
dedicated/special purpose
computers
– timeshared systems
– functionally modular systems
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What is distributed …
• Processing logic
• Functions
• Data
• Control
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What is a Distributed Database System?
A distributed database (DDB) is a collection of multiple,
logically interrelated databases distributed over a computer
network.
A distributed database management system (D–DBMS) is
the software that manages the DDB and provides an
access mechanism that makes this distribution transparent
to the users.
Distributed database system (DDBS) = DDB + D–DBMS
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What is not a DDBS?
• A timesharing computer system
• A loosely or tightly coupled multiprocessor system
• A database system which resides at one of the
nodes of a network of computers - this is a
centralized database on a network node
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Centralized DBMS on a Network
Site 1
Site 2
Site 5
Communication
Network
Site 4
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Site 3
Distributed DBMS Environment
Site 1
Site 2
Site 5
Communication
Network
Site 4
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Site 3
Implicit Assumptions
• Data stored at a number of sites  each site logically
consists of a single processor.
• Processors at different sites are interconnected by a
computer network  no multiprocessors
– parallel database systems
• Distributed database is a database, not a collection of
files  data logically related as exhibited in the users’
access patterns
– relational data model
• D-DBMS is a full-fledged DBMS
– not remote file system, not a TP system
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Shared-Memory Architecture
P1
Pn
M
D
Examples : symmetric multiprocessors (Sequent,
Encore) and some mainframes
(IBM3090, Bull's DPS8)
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Shared-Disk Architecture
P1
Pn
M1
Mn
D
Examples : DEC's VAXcluster, IBM's IMS/VS
Data Sharing
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Shared-Nothing Architecture
P1
M1
D1
Pn
Dn
Mn
Examples : Teradata's DBC, Tandem, Intel's
Paragon, NCR's 3600 and 3700
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Applications
• Manufacturing - especially multi-plant
manufacturing
• Military command and control
• EFT
• Corporate MIS
• Airlines
• Hotel chains
• Any organization which has a
decentralized organization structure
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Distributed DBMS Promises
 Transparent management of distributed,
fragmented, and replicated data
 Improved reliability/availability through
distributed transactions
 Improved performance
 Easier and more economical system expansion
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Transparency
• Transparency is the separation of the higher level
semantics of a system from the lower level implementation
issues.
• Fundamental issue is to provide
data independence
in the distributed environment
– Network (distribution) transparency
– Replication transparency
– Fragmentation transparency
• horizontal fragmentation: selection
• vertical fragmentation: projection
• hybrid
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Example
ASG
EMP
ENO
ENAME
TITLE
E1
E2
E3
E4
E5
E6
E7
E8
J. Doe
M. Smith
A. Lee
J. Miller
B. Casey
L. Chu
R. Davis
J. Jones
Elect. Eng.
Syst. Anal.
Mech. Eng.
Programmer
Syst. Anal.
Elect. Eng.
Mech. Eng.
Syst. Anal.
ENO PNO
PROJ
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E1
E2
E2
E3
E3
E4
E5
E6
E7
E7
E8
P1
P1
P2
P3
P4
P2
P2
P4
P3
P5
P3
RESP
Manager
Analyst
Analyst
Consultant
Engineer
Programmer
Manager
Manager
Engineer
Engineer
Manager
DUR
12
24
6
10
48
18
24
48
36
23
40
PAY
PNO
PNAME
BUDGET
TITLE
SAL
P1
P2
P3
P4
Instrumentation
Database Develop.
CAD/CAM
Maintenance
150000
135000
250000
310000
Elect. Eng.
Syst. Anal.
Mech. Eng.
Programmer
40000
34000
27000
24000
Transparent Access
SELECT
FROM
WHERE
AND
AND
ENAME,SAL
EMP,ASG,PAY
DUR > 12
EMP.ENO = ASG.ENO
PAY.TITLE = EMP.TITLE
Tokyo
Paris
Boston
Communication
Network
Paris projects
Paris employees
Paris assignments
Boston employees
Boston projects
Boston employees
Boston assignments
Montreal
New
York
Boston projects
New York employees
New York projects
New York assignments
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Montreal projects
Paris projects
New York projects
with budget > 200000
Montreal employees
Montreal assignments
Distributed Database - User View
Distributed Database
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Distributed DBMS - Reality
DBMS
Software
DBMS
Software
DBMS
Software
User
Query
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User
Query
User
Application
DBMS
Software
Communication
Subsystem
User
Query
DBMS
Software
User
Application
Potentially Improved Performance
• Proximity of data to its points of use
– Requires some support for fragmentation and replication
• Parallelism in execution
– Inter-query parallelism
– Intra-query parallelism
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Parallelism Requirements

Have as much of the data required by each
application at the site where the application
executes
– Full replication
• How about updates?
– Updates to replicated data requires implementation of
distributed concurrency control and commit protocols
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System Expansion
• Issue is database scaling
• Emergence of microprocessor and workstation
technologies
– Demise of Grosh's law
– Client-server model of computing
• Data communication cost vs telecommunication
cost
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Distributed DBMS Issues
• Distributed Database Design
– how to distribute the database
– replicated & non-replicated database distribution
– a related problem in directory management

Query Processing
– convert user transactions to data manipulation instructions
– optimization problem
– min{cost = data transmission + local processing}
– general formulation is NP-hard
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Distributed DBMS Issues

Concurrency Control
– synchronization of concurrent accesses
– consistency and isolation of transactions' effects
– deadlock management
•
Reliability
– how to make the system resilient to failures
– atomicity and durability
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Relationship Between Issues
Directory
Management
Query
Processing
Distribution
Design
Concurrency
Control
Deadlock
Management
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Reliability
Struktur Data/File
37
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1
HIERARKI DATA DIGITAL (BINARY DIGIT)
DIGITAL
0
ANALOG
BIT
BYTE
1
8
UNICODE=16BIT=>65000CRKTR
WORD
DATABASE
RECORD
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DATA FILE
Representing Pictures, Time
•
Pictures
– Pixel : Ukuran ketajaman/detail jumlah cell dalam tiap inchi
Time
– Millisecond = 1/1000 seconds
– Microsenond = 1/1,000,000
– Nanosecond = 1/1,000,000,000
– Picosencond = 1/1,000,000,000,000
•
Representing Size of Bytes
•
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Size is measured by the number of bytes
– KB
-Kilobyte = 1,000 bytes (actually 1024)
– MB
-Megabyte = 1,000 kilobytes = 106 bytes
– GB
-Gigabyte = 109 bytes
– TB
-Terabyte = 1012 bytes
– PB
-Petabyte = 1015 bytes
– Exabyte - = 1018 bytes
Format Data Base
40
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Hirarkis Data
•
•
•
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Hirarkis data meliputi bit, ruas, rekod, dan file, yang merupakan
unsur-unsur suatu database.
Data dapat dikelompokkan menurut hirarki kategori, masingmasing terus meningkat ke yang lebih kompleks.
Hirarki penyimpanan data terdiri dari tingkatan data disimpan: bit,
byte (karakter), ruas, rekord, file, dan database
Hirarkis Data
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Sistem Manajemen Database
Apakah yang dimaksud dengan sistem manajemen database? (Database
Management System=DBMS).
•
Sistem manajemen database adalah sistem berbasis komputer untuk
mendefinisikan, membuat, memanipulasi, mengawasi, mengatur, dan
menggunakan database.
•
Sebuah database adalah kumpulan dari integrasi data yang terorganisir
seperti byte, ruas, rekod, dan file.
•
DBMS adalah menggantikan sistem manajemen file lama dan dengan
demikian meningkatkan integritas data dan kemandirian, serta
mengurangi pemborosan data
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Manajemen File v.s. Manajemen Database
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Fundamental DBMS
•
•
•
•
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DMBS membutuhkan kapasitas penyimpanan
besar, biasanya menggunakan magnetic tape, hard
disk, CD-ROM, dan sistem penyimpanan (mass
storage systems).
Perangkat lunak DBMS biasanya termasuk bahasa
query, penulis laporan, utiliti, kamus data, dan log
transaksi.
Perangkat keras: Menghitung kapasitas
penyimpanan
Perangkat lunak: Pengawasan
Perangkat Lunak dan Contoh Laporan dari DBMS
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Kamus Data dan Log Transaksi
Paket Perangkat Lunak Database
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Jenis Organisasi Database
Tiga jenis umum struktur database adalah:
•
Hirarkis: pada struktur database hirarkis, ruas atau
rekod diatur dalam kelompok yang berhubungan
menyerupai ranting pohon
•
Jaringan: database jaringan hampir sama dengan
hirarkis, tetapi masing-masing anak rekod dapat
memiliki induk lebih dari satu rekod
•
Relasional: Jenis pengorganisasian yang paling
fleksibel, database relasional menghubungkan data di
dalam file berbeda melalui penggunaan suatu ruas
kunci, atau elemen data umum
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Database Hirarkis
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Database Jaringan
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Database Relasional
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Format File dalam project audit/tabel data
Open Data Base Conectifity
Delimited files
Text File
Acces File
EXCEL File
DBF File
Dat File
PNG File
ACL format File
PDF File
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