The Internet Database Environment

1. The InternetDatabase Environment Chapter 10

2. Objectives • Describe environment for Internet database connectivity • Describe Internet-based business environment • Use and define Internet-related terminology • Explain purpose of client-side and server-side extensions • Describe web services and their use for e-commerce • Describe issues for Web-site management • Discuss Web security and privacy issues

3. Business on the Internet • Electronic Business (e-business) • Development of integrated relationship with customers and suppliers via the Internet • Business-to-Consumer (B2C) – retail • Business-to-Business (B2B) – interaction with suppliers and vendors • Electronic Commerce (e-commerce) • Business transactions, including: • Order processing/fulfillment • Customer relations (CRM) • Electronic data interchange (EDI) • Bill payments

4. Web-Related Terms • World Wide Web (WWW) • The total set of interlinked hypertext documents residing on Web servers worldwide • Browser • Software that displays HTML documents and allows users to access files and software related to HTML documents • Web Server • Software that responds to requests from browsers and transmits HTML documents to browsers • Web pages – HTML documents • Static Web pages – content established at development time • Dynamic Web pages – content dynamically generated, usually by obtaining data from database

5. Figure 10-1: Database-enabled Intranet-internet Environment

6. Some Common Protocols • TCP/IP (Internet Protocol) • TCP (Transport Control Protocol) - used to break apart and rebuild information that travels over the Internet • IP (Internet Protocol) - the main delivery system for info over the Internet • HTTP (Hyper Text Transfer Protocol) • Used for Web pages • Communication protocol used to transfer pages from Web server to browser • HTTPS is a more secure version

7. Commonly Used Protocols • https • Using an https: URL indicates that HTTP is to be used, but with a different default port and an additional encryption/authentication layer between HTTP and TCP. • Invented by Netscape • Provide authentication and encrypted communication • Widely used on the Web for security-sensitive communication, such as payment transactions

8. Some Common Protocols • FTP (File Transfer Protocol) • Used to download and upload files • SMTP (Simple Mail Transport Protocol) • Used to send text-based information (e-mail) • Telnet • Used to perform commands on a remote computer

9. Communications Technology • IP Address • An IP (Internet Protocol) address is a unique identifier for a node or host connection on a network. • An IP address is a 32 bit binary number usually represented as 4 decimal values, each in the range 0 to 255 separated by decimal points (periods/dots) Example: 140.179.220.200 • Every IP address consists of two parts: • One part identifying the network (network address) • One part identifying the node

10. Figure 10-2: Typical URL Communications Technology • DNS -Domain Name Service • Makes it possible to attach easy-to-remember domain names (such as "wikipedia.org") to hard-to-remember IP addresses (such as 207.142.131.206). • Uniform Resource Locator (URL) • Mnemonic Web address corresponding with IP address • Can include folder location and html file name

11. Markup Language • Combines text and extra information about the text such as the structure or presentation. <b> Hello </b> <u> World </u> HelloWorld • HTML (HyperText Markup Language) is one of best-known markup languages • Used in the publishing industry in the communication of printed work between authors, editors, and printers.

12. Internet-Related Languages Standards and Web conventions established by World Wide Web Consortium (W3C) • HTML: Hypertext Markup Language • Markup language specifically for Web pages • SGML: Standard Generalized Markup Language • Markup language standard • XML: Extensible Markup Language • Simplified subset of SGML • Markup language allowing customized tags • XHTML • XML-compliant extension of HTML

13. Internet Related Languages • SGML is used to write the electronic version of the Oxford English Dictionary. • Sophisticated queries can be performed, as well as easy translation into HTML.

14. Internet-Related Languages • Java • Object-oriented programming language for applets • JavaScript / VBScript • Scripting languages that enable interactivity in HTML documents

15. JavaScript Code in a Web Page • Use the <script> tag and set the language attribute to “javascript.” • Your browser retrieves and reads the page from top to bottom, displaying the results of the HTML code and executing JavaScript statements as it goes. (javascript.htm) <h1 align=”center”> Scripting </h1> This is text before the script <br> <script language=”javascript”> <!-- // Writing text on a Web Page document.write (“Welcome”) // Displaying an alert dialog box alert(“You are creating your first script”) // --> </ script> This is text after the script<br>

16. Internet-Related Languages • Style Sheets • Cascading Style Sheets (CSS) • Control appearance of Web elements in an HTML document • XSL and XSLT • XSL style sheet for XML documents • XSLT used to create HTML documents from XML documents

17. p { font-family: "Garamond", serif; } • h2 { font-size: 110%; color: red; background: white; } CSS <p> This is a segment of html code</p> <h2> Header. This header appears in red </h2> HTML Internet Related Languages • Cascading Style Sheets • Used to define colors, fonts, layout, and other aspects of document presentation. • Enables the separation of document content (written in HTML) from document presentation (written in CSS) • They are called cascading because more than one can be applied to a Web page

18. Web Servers • Provide HTTP service to many clients at once • Load balancing approaches: • Domain Name Server (DNS) balancing • One DNS = multiple IP addresses • Place copies of the website on multiple physical servers • DNS returns either a different IP address for each DNS request or a collection of IP addresses • Software/hardware balancing • Only one IP address is published for site • Request at one IP address is distributed to multiple servers • Reverse proxy • All connections coming from the Internet addressed to one of the web servers are routed through the proxy server, • Either processes request locally pass the request to web server. • Store frequently used responses. • Intercept client request - use cached response instead of contacting server

19. Figure 10-3: Web-to-database middleware Server-Side Extensions • Programs that interact directly with Web servers to handle requests • e.g. database-request handling middleware

20. Web Server Interfaces • Common Gateway Interface (CGI) • Specify transfer of information between Web server and CGI program • Performance not very good • Security risks • Application Program Interface (API) • More efficient than CGI • Shared as dynamic link libraries (DLLs) • Java Servlets • Like applets, but stored at server • Cross-platform compatible • More efficient than CGI

21. Client-Side Extensions • Add functionality to the browser • Plug-ins • hardware./software modules that extend browser capabilities by adding features (e.g. encryption, animation, wireless access) • ActiveX • Microsoft COM/OLE components that allow data manipulation inside the browser • Cookies • Block of data stored at client by Web server for later use

22. Web-to-Database Tools • Active Server Pages (ASP) • Microsoft server-side scripting language • Generates dynamic Web pages • Interfaces to databases in MS Windows-based Web servers • Cold-Fusion • Uses special server-side markup language CFML • Modeled after HTML • Interfaces to databases • Embedded SQL • SQL embedded in 3GL programs • Provides flexible interface • Improves performance • Improves database security

23. Managing Website Data • Web Security Issues • Prevent unauthorized access and malicious destruction • Privacy Issues • Protect users’ privacy rights • Internet Technology Rate-of-Change Issues • Deal with rapid advances in technology

24. Web Security • Planning for Web Security • Risk assessment: nature, likelihood, impact, and motivation of security risks • Network Level Security • Web server and DB server on separate LAN from other business systems • Minimize sharing of hard disks among network servers • Regular monitoring of network and firewall logs • Install probe-monitor software

25. Web Security (continued) • Operating System Level Security • Patch all known OS vulnerabilities • Install anti-virus software with boot-time, file download time, and email reception time virus detection • Monitor server logs for unauthorized activity • Disable services not required to reduce risk of unauthorized access

26. Web Security (continued) • Web Server Security • Restrict number of users on Web server • Restrict access (minimize number of open ports) • http and https only, if possible • Remove unneeded programs • Restrict CGI scripts to one subdirectory • For Unix, only install minimum software for Web server

27. Web Security (continued) • Firewall – hardware/software security component that limits external access to company’s data • Proxy server – firewall component that manages Internet traffic to and from a LAN • Router – intermediate device that transmits message packets to correct destination over most efficient pathway • Intrusion Detection System (IDS) – system that identifies attempt to hack or break into a system

28. Routers to transmit message packets to correct destination Firewall to limit external access to data IDS to monitor and recognize security breach attempts Figure 10-11: Establishing Internet Security

29. Firewall • A program or hardware device that filters the information coming through the Internet connection into your private network. • Incoming packets of information flagged by the filters are not allowed through. • A company can place a firewall at every connection to the Internet • At every T1 line coming into the company) • Can implement security rules and encryption

30. Firewalls • Methods to control traffic flowing in and out of the network: • Packet filtering • Packets (small chunks of data) are analyzed against a set of filters. • Proxy service • Information from the Internet is retrieved by the firewall and then sent to the requesting system and vice versa. • Stateful inspection • Anewer method that doesn't examine the contents of each packet but instead compares certain key parts of the packet to a database of trusted information.

31. Routers • Routers are specialized computers that send your messages and those of every other Internet user to their destinations along thousands of pathways. • Let messages flow between networks, rather than within networks. • A router essentially has two separate but related jobs: • Ensure that information doesn't go where it's not needed -- crucial for keeping large volumes of data from clogging the bandwidth. • Ensure that information does make it to the intended destination.