Matakuliah
Tahun
Versi
: T0604-Pengantar Teknologi Informasi
: 2008
: 2.0/0.0
Pertemuan 17
Basisdata (Databases)
Sumber:
Chapter 8. Databases &
Information Systems: Digital
engines for today’s economy, p.407
Williams, B.K, Stacy C. Sawyer (2007).
Using Information Technology: A
Practical Introduction to Computers &
Communications. Seventh Edition,
McGraw-Hill, New York. ISBN-13: 978-007-110768-6
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• menjelaskan: hierarkhi data, key-filed, tipe
file, metode akses dan penyimpanan data;
pengertian dan keuntungan sistem
manajemen basisdata, dan jenis-jenis
akses basisdata yg utama(C2)
2
Outline Materi
• Managing Files: Basic Concepts
• Database Management Systems
3
Managing Files: Basic
Concepts
• A database is a logically organized
collection of related data designed and
built for a specific purpose
• Data is stored hierarchically for easier
storage and retrieval
• Files: collections of related records
• Records: collections of related fields
•
•
Field: unit of data containing 1 or more
characters
Character: a letter number or special
character made of bits
•
Bit: a 0 or 1
8-4
Managing Files: Basic
Concepts
• Key Field – the field that identifies a record
– Often an identifying number, such as social security
number
– Primary keys must be unique
• Keys are used to pick records out of a database
• Unique keys make records stand out from each other
• If two records had the same key, then you might not pick the
correct one
– Nonprimary keys are used to sort records in different ways
– Foreign keys are fields that appear in two different tables and
are used to relate one table to another
8-5
Managing Files: Basic Concepts
8-6
This example
shows a
sample
database in
Microsoft
Access.
Products is a
table.
ProductID is the
primary key of
the Product
table.
ProductID is
also a foreign
key in the
Orders table
Managing Files: Basic Concepts
• Program files are files containing software
instructions
– Source program files are written by the
software developer in the programming
language
• Double-clicking on them won’t run them
• They have file extensions like .cpp, .jav, .bas
– Executable files are program files translated
so they can be executed on the computer
• Double-clicking on them will cause them to run
• They have file extensions like .exe or .com
8-7
Managing Files: Basic Concepts
• Data files are files that contain data such as
words, numbers, pictures, or sounds
– These are the files that are used in databases
– They have extensions such as .txt .mdb, and .xls
– Graphics files have extensions like .tiff, .jpeg, and
.png
– Audio files have extensions such as .mp3, .wav, and
.mid
– Animation/video files have extensions such as .qt,
.mpg, .avi, and .rm
• Data files are often compressed to save space
and transmit them faster
– Compression removes repetitive elements from a file
8-8
Database Management Systems
• Software written specifically to control the
structure of a database and access to the data
– Reduced data redundancy
• Redundant data is stored in multiple places, which causes
problems keeping all the copies current
– Improved data integrity
• Means the data is accurate, consistent, and up to date
– Increased security
• Limits who can create, read, update, and delete the data
– Ease of data maintenance
• Offer validation checks, backup utilities, and procedures for
data inserting, updating, and deletion
8-9
Database Management Systems
3 Principal Components
• Data Dictionary
– A repository that stores the data definitions and
descriptions of the structure of the data and the
database
• DBMS Utilities
– Programs that allow you to maintain the database by
creating, editing, deleting data, records, and files
– Also include automated backup and recovery
• Report Generator
– Program for producing an on-screen or printed
document form all or part of a database
8-10
Database Management Systems
Database Administrator
• Database Administrator (DBA)
– A high-paid, responsible position within an
organization
– Coordinates all related activities and needs for an
organization’s database
– Ensures the database’s
•
•
•
•
•
•
Discussion Question: Did
you know that 93% of
companies that lost their
data center for 10 days or
more due to a disaster filed
for bankruptcy within a
year?
Recoverability
Integrity
Security
Availability
Reliability
Performance
8-11
Kesimpulan
12