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Basisdata (Databases)

Williams, B.K, Stacy C. Sawyer (2007). Using Information Technology: A Practical Introduction to Computers & Communications. Seventh Edition, McGraw-Hill, New York. ISBN-13: 978-0-07-110768-6

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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)

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Outline Materi

• Managing Files: Basic Concepts

• Database Management Systems

• Database Models

• Data Mining

• The Ethics of Using Databases

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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

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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

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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 Orders table

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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

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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

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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

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Database Management Systems3 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

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Database Management SystemsDatabase 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 year?

• 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.

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Database Management SystemsDatabase Administrator

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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

– Oldest and simplest; used in mainframes

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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– Requires the database structure to be defined in advance

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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– Query by Example uses sample records or forms to

allow users to define the qualifications for choosing records

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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• Hypermedia database

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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

– Use OLAP (Online Analytical Processing) software to provide answers to complex database queries

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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 Warehouse is a special database that shows detailed and summary data from multiple sources

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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

applied to data sets with more than just numerical data

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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

– Retail stores use it to predict future purchase patterns to help them choose which products to stock for the future

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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

Discussion Question: Has any one had their identity stolen? How long did it take you to get it straightened out?

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