Basisdata (Databases)
Williams, B.K, Stacy C. Sawyer (2007).
Using Information Technology: A Practical Introduction to Computers & Communications. Seventh Edition,
978-0-2
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
Outline Materi
• Managing Files: Basic Concepts
• Database Management Systems
• Database Models
• Data Mining
8-4
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
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
8-6
Managing Files: Basic Concepts
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
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
8-8
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
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
8-10
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
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
• Recoverability • Integrity • Security • Availability • Reliability • Performance
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
• U.S. businesses lose over $12 billion per year because of data loss. • Hardware or system failure accounts for 78% of all data loss.
• Human error accounts for 11% of all data loss.
• Software corruption account for 7% of all data loss. • Natural disasters account for only 1% of all data loss. • More vital data is being stored in smaller spaces.
• Instant access to electronic data has become more crucial in day-to-day business.
• Disaster prevention and recovery plans are often overlooked or outdated. • Backup tools and techniques are not 100% reliable.
• 93% of companies that lost their data center for 10 days or more due to a disaster filed for bankruptcy within one year of the disaster.
12
Database Management Systems
Database Models
• Hierarchical Databases
– Fields or records are arranged in related groups resembling a family tree with child (low-level) records subordinate to parent (high-level) records
– Root record is the parent record at the top of the database, and data is accessed through the hierarchy
8-14
Database Models
• Network Database
– Similar to a hierarchical database, but each child record can have more than one parent record
– Used principally with mainframe computers
Database Models
• Relational Database
– Relates or connects data in different files through the use of a key, or common data element
– Examples are Oracle, Informix, Sybase
– Data exists independently of how it is physically stored
– Users don’t need to know data structure to use the database
– Uses SQL (structured query language) to create, modify, maintain, and query the data
8-16
Database Models
• Object-oriented Databases
– Use “objects”, software written in small, manageable chunks, as elements within data files
– An object consists of
• Data in any form, including audio, graphics, and video • Instructions on the action to be taken with the data
– Examples include FastObjects, GemStone, Objectivity DB, Jasmine Object Database, and KE Express
– Types include
• Web database
Database Models
• Multidimensional Database
– Models data as facts, dimensions, or
numerical answers for use in the interactive
analysis of large amounts of data for
decision-making purposes
– Allows users to ask questions in colloquial
English
8-18
Data Mining
• Is the computer-assisted process of sifting
through and analyzing vast amounts of data to
extract hidden patterns and meaning and to
discover new knowledge
• Data is fed into a Data Warehouse through the
following steps
– Identify and connect to data sources – Perform data fusion and data cleansing
– Obtain both data and meta-data (data about the data) – Transport data and meta-data to the Data Warehouse
Data Mining
• Methods for searching for patterns in the
data and interpreting the results
– Regression analysis
• Develops a formula to fit patterns in the data that has been extracted
• Formula is applied to other data sets to predict future trends
– Classification analysis
• A statistical pattern recognition process that is
8-20
Data Mining
• Applications include
– A phone company identifying customers with
large bills, who were really small businesses
trying to pay the cheaper residential rate
– A coach in the Gymnastics Federation used it
to discover what long-term factors contributed
to athletes’ performance
The Ethics of Using Databases
• Identity Theft concerns
– A crime in which thieves hijack your identity
and use your good credit rating to get cash,
take out loans, order credit cards, and buy
things in your name
• Privacy concerns
– Name migration: getting endless junk mail
and telemarketing calls
– Résumé rustling and online snooping
– Government prying and spying
22
