Basisdata (Databases)

1. 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

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 manajemen basisdata, dan jenis-jenis akses basisdata yg utama(C2)

3. Outline Materi • Managing Files: Basic Concepts • Database Management Systems • Database Models • Data Mining • The Ethics of Using Databases

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 • Bit: a 0 or 1

5. 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

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 Orders table

7. 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. 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

9. 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

10. 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

11. 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?

12. Database Management SystemsDatabase Administrator • 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.

13. 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

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 • Requires the database structure to be defined in advance

15. 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

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 • Hypermedia database

17. 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

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

19. 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

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

21. 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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