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Copyright © 2003 Addison-Wesley Overview of Information Systems What is the Internet? Why are databases important? How do databases represent information? Who works with databases? How do databases support the World Wide Web? What database concepts and terms do you need to know?

Copyright © 2003 Addison-Wesley What is the Intenet? Collection of computers –With networking infrastructure Software and communications –Web server –Web browser –Communications strategy Networked computers can be –Server –Desktop –Notebook –Handheld –Mobile phone

Copyright © 2003 Addison-Wesley Why Are Databases Important? Importance to business –Walmart: Records of retail business Size of warehouses Size of inventory Average sales per $ of inventory –LL Bean: Records of customers Importance to Web –Records of interactions –Example of auction site –Example of enthusiasts site

Copyright © 2003 Addison-Wesley Importance of Databases to Economy Expanding use of databases in retail sales –Walmart, retail sales information tracking –LL Bean, catalog sales information tracking Examples of analyses –Sales of items Comparisons between daily totals of items sold and items in inventory Seasonal variations in sales of specific and similar items Relative sales of similar items with different features –Market-basket collections (all items in a single purchase) Average and variation in total purchase amount Average and variation in number and price of items Correlation between sales of items in a single purchase –Customer analysis Behavior of average customer Preferences of individual customers

Copyright © 2003 Addison-Wesley How Do Databases Represent Information? The physical database: – a collection of files containing the data content The schema: –a specification of the physical database’s information content and logical structure The database engine: –software that lets people access and modify the database contents The data definition and manipulation languages: –programming languages, such as Java or SQL (Structured Query Language), that let software developers define the schema and access the database

Copyright © 2003 Addison-Wesley How Do Databases Represent Information? Relational database management system (RDBMS) –Tables of data –Schema Name of table Names and types of attributes –Contents Row is a fact Attribute value is a characteristic

Copyright © 2003 Addison-Wesley Example of storing customer information Customer table accountIdlastNamefirstName 101BlockJane 102HamiltonCherry 103HarrisonKate 104BreauxCarroll Logical description (Schema) Customer (accountId, lastName, firstName) Table creation statement create table Customer (accountId integer, lastName char(20), firstName char(20))

Copyright © 2003 Addison-Wesley Client Server Database Interaction

Copyright © 2003 Addison-Wesley Who Works with Database Systems? Database designers Applications developers Web-application developers Web-site designers Database administrators

Copyright © 2003 Addison-Wesley How Do Databases Support the World Wide Web? Maintain information that is published in the site Track the ways in which site visitors use that information Track the number of site visitors and customers Store information collected from input forms such as requests for customer addresses Store the structure and content of Web pages Sample: tId=101 tId=101

Copyright © 2003 Addison-Wesley Sample BigHit Video Reservations Schema: Reservation (accountId, movieTitle) accountIdmovieTitle 101Annie Hall 165The Thirty-Nine Steps 101Animal House 453Annie Hall

Copyright © 2003 Addison-Wesley Timeline for Database Systems Developments before 1960 transition from punched card and tape 1960s, from file management to databases –Bachman (GE) IDS and data structure diagrams –IMS from IBM, Hierarchical Data Model –IMS DB/DC, Network Model and communication –SABRE, multi-user access with network 1970s, CODASYL and Relational Model –Codd (IBM) Relational Model –Chen introduced Entity Relationship Model –Query languages developed (SQL) 1980s, Client/Server DBs, Oracle, DB2 –PC databases, DBase, Paradox, etc. –SQL standard for definition and manipulation 1990s, web-based information delivery –Trends: expert DBs, object DBs, distributed DBs 2000s, Enhancing database technology for Web storage and access –Bioinformatics: genetic and protein information, medical records –Using the Web as a database