15 Chapter 15 Web Database Development Database Systems

15 Chapter 15 Web Database Development Database Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel

15 In this chapter, you will learn: • How Internet databases are typically used • About the architecture of Web-to-database middleware • How Web-to-database middleware (Cold. Fusion) is used to integrate databases with the Internet • What special considerations govern Web database development Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 2

15 Web Database Connectivity • Allows rapid response to competitive pressures – New services – New products • Customer support enhanced • Fast effective information dissemination – Universal access – Local – Around the globe Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 3

15 Typical Uses of Internet Table 15. 2 Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 4

15 Characteristics/Benefits of Internet Technology • Hardware & software independence – – Cost savings Uses existing equipment Platform independence and portability No need for multiple platform development • Common simple user interface – Reduced training – Reduced support Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 5

15 Characteristics/Benefits of Internet Technology (con’t. ) • Location Independence – Global access through Internet – Reduced costs for dedicated connections • Rapid development at manageable costs – Development tools – Low entry costs – Available software & access tools Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 6

15 Web-to-Database Middleware • Server-side extension – – Interacts directly with Web server Handles specific requests Also known as Web-to-database middleware Examples • Cold. Fusion • CGI • API Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 7

15 Web-to-Database Middleware Figure 15. 1 Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 8

15 Web Server Interfaces • Common Gateway Interface (CGI) – Uses script files to connect to database – Perl, C++, VB • Application Programming Interface (API) – – Newer and more efficient Uses DLLs Memory resident and faster Well known APIs • Netscape (NSAPI) • Internet Server API from Microsoft (ISAPI) • Web. Site API from O’Reilly (WSAPI) Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 9

15 API and CGI Web Server Interfaces Figure 15. 2 Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 10

15 Web-to-Database Middleware Connection Methods • Native SQL access middleware • Use services of Open Database Connectivity (ODBC) • Use Object Linking and Embedding Database (OLE DB) interface with Windows • ODBC most common Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 11

15 ODBC to Access Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel Figure 15. 3 12

15 Web-to-Database Middleware Uses ODBC to Access Databases Figure 15. 4 Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 13

15 Web Browser • • • Located on the client computer End user Web interface Interprets HTML code received from Web server Presents page components in a standard way Client-side extensions – Plug-ins – Java and Java. Script – Active. X and VBScript Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 14

15 Cold. Fusion • Web application server • Uses – – – – Connect and query database from Web page Present database data in a Web page Create dynamic Web search pages Create Web pages to insert, update, and delete data Define required and optional relationships Define required and optional form fields Enforce referential integrity in form fields Use simple and nested queries to represent business rules Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 15

15 How Cold. Fusion Works Figure 15. 5 Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 16

15 How Cold. Fusion Works • Server-side markup language – HTML extensions – Cold. Fusion Markup Language (CFML) • • Executed in interpreter mode Contain HTML, CFML May contain Java, Java. Script, or VBScript Client browser requests. cfm page from Web Server – Cold. Fusion application server executes. cfm script – Sends resulting output in HTML to Web Server – Web server sends to client browser Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 17

15 Cold. Fusion Tags • CFQuery – Queries a database • CFOutput – Displays data returned by query • CFTable – Displays data in Tabular format Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 18

15 Cold. Fusion Dynamic Query • Create script to generate form with criteria used in database search • Create script to execute query and display results – Uses Cold. Fusion tags – Uses HTML Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 19

15 The Web as a Stateless System • Web server does not know status of any client at any given time • Request-reply model of communication • Browser concerned only with current page • Data processing requires additional software – Java, Java. Script, VBScript Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 20

15 INSERTs and UPDATEs with Cold. Fusion • CFINSERT Tag – Adds records to database – Parameters • DATASOURCE • TABLENAME • CFUPDATE Tag – Updates selected database contents – Parameters • DATASOURCE • TABLENAME Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 21

15 DELETEs with Cold. Fusion • CFQUERY Tag – Uses SQL DELETE Statement – Parameters • DATASOURCE • TABLENAME Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 22

15 Internet Database: Special Considerations • Involve more than just database-enabled Web applications • Issues important to corporate databases – – Data security Transaction management Client-side data validation Operational and management challenges • Database applications development most affected by Internet Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 23

15 Supported Data Types • Integrated data from multiple sources – – • • Word-processor documents Pictures Sounds Movies Methods for storing and extracting data objects Overhead created by storage Client browser support of object being accessed Size of database considering multimedia and other data Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 24

15 Data Security • Web Server Level – Secure transactions using encryption – TCP/IP protocol level – Firewalls • RMDBS Vendors – Login authentication – Restrict access to particular SQL commands • Web-to-database middleware – End user restrictions – Designer created algorithms • Must support e-commerce applications Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 25

15 Transaction Management • Concept is foreign to Web • Dilemma created by request-reply model – Web cannot maintain open line between client and database – Recovery requires client maintain open communications • Designers must ensure proper transaction management support at database server level • Cold. Fusion uses CFTRANSACTION tag for transaction management support Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 26

15 Denormalization • Web forms – Cannot use multiple data entry lines – 1: M relationships problematic • Solutions – Web programming languages – Java, Java. Script, VBScript Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 27