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Web Database Development

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Database Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel ... About the architecture of Web-to-database middleware ... – PowerPoint PPT presentation

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Title: Web Database Development


1
Chapter 15
  • Web Database Development
  • Database Systems Design, Implementation, and
    Management, Fifth Edition, Rob and Coronel

2
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 (ColdFusion) is
    used to integrate databases with the Internet
  • What special considerations govern Web database
    development

3
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

4
Typical Uses of Internet
Table 15.2
5
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

6
Characteristics/Benefits of Internet Technology
(cont.)
  • 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

7
Web-to-Database Middleware
  • Server-side extension
  • Interacts directly with Web server
  • Handles specific requests
  • Also known as Web-to-database middleware
  • Examples
  • ColdFusion
  • CGI
  • API

8
Web-to-Database Middleware
Figure 15.1
9
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)
  • WebSite API from OReilly (WSAPI)

10
API and CGI Web Server Interfaces
Figure 15.2
11
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

12
ODBC to Access Databases
Figure 15.3
13
Web-to-Database Middleware Uses ODBC to Access
Databases
Figure 15.4
14
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 JavaScript
  • ActiveX and VBScript

15
ColdFusion
  • 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

16
How ColdFusion Works
Figure 15.5
17
How ColdFusion Works
  • Server-side markup language
  • HTML extensions
  • ColdFusion Markup Language (CFML)
  • Executed in interpreter mode
  • Contain HTML, CFML
  • May contain Java, JavaScript, or VBScript
  • Client browser requests .cfm page from Web Server
  • ColdFusion application server executes .cfm
    script
  • Sends resulting output in HTML to Web Server
  • Web server sends to client browser

18
ColdFusion Tags
  • CFQuery
  • Queries a database
  • CFOutput
  • Displays data returned by query
  • CFTable
  • Displays data in Tabular format

19
ColdFusion Dynamic Query
  • Create script to generate form with criteria used
    in database search
  • Create script to execute query and display
    results
  • Uses ColdFusion tags
  • Uses HTML

20
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, JavaScript, VBScript

21
INSERTs and UPDATEs with ColdFusion
  • CFINSERT Tag
  • Adds records to database
  • Parameters
  • DATASOURCE
  • TABLENAME
  • CFUPDATE Tag
  • Updates selected database contents
  • Parameters
  • DATASOURCE
  • TABLENAME

22
DELETEs with ColdFusion
  • CFQUERY Tag
  • Uses SQL DELETE Statement
  • Parameters
  • DATASOURCE
  • TABLENAME

23
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

24
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

25
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

26
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
  • ColdFusion uses CFTRANSACTION tag for transaction
    management support

27
Denormalization
  • Web forms
  • Cannot use multiple data entry lines
  • 1M relationships problematic
  • Solutions
  • Web programming languages
  • Java, JavaScript, VBScript
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