INTERNET DATABASE Chapter 9

u Basics of Internet, Web, HTTP, HTML, URLs. u Advantages and disadvantages of Web as a database platform. u Approaches for integrating databases into Web: –Scripting Languages –Common Gateway Interface (CGI) –HTTP Cookies Chapter 29 - Objectives

Internet and E-commerce u Internet – a worldwide collection of interconnected computer network u E-commerce – customers can place and pay for orders via the business’s web site (Amazon.com) u Benefits of e-commerce –Worldwide market – buy from anywhere –Productivity – no wastage of time –Cost reduction – less time & energy –Improved customer services – ease the customer (faqs, knowledge on products, other services)

Internet Services u – to send mail and file attachment u Worldwide web – to browse for information stored anywhere and do business transaction u File transfer – to download and upload file u News – to join a news group u Chat room – to join a discussion or chat room

Worldwide web u Internet – computers connected using a standard protocol : TCP/IP u Worldwide web – resources stored on the web u Web browser – software to browse the web (IE..) u Web server – software to responds to client’s request u Web page – text written in HTML, static and dynamic

u Hyperlink – linking the web page u Hypertext – refer to different types of documents (text, graphics, images…in the hyperlink) u Web site – refer to server and collection of the web pages u http (hypertext transfer protocol) – protocol used by client and server to communicate Worldwide web (cont.)

Client Functions u Can be extended : –Plug-ins – browser can activate automatically when required – external application (exp: if file ext. is.pdf then launches Adobe Acrobat Reader) –Active-X – Microsoft’s specification for writing programs that will run inside its browser. - It extends the browser’s ability by providing controls such as calendar and calculator. - These controls allows to manipulate data within the browser. Controls usually written in VB or Visual C++

–VBScript – Microsoft product based on Visual Basic - HTML page containing embedded code written in VBScript - can be executed by web browser –JavaScript – Netscape product (Netscape Communicator) –Java – Product of Sun. It runs on top of a web browser/applets. Java routines are compiled and stored in server. HTML contain calls to the routines. Browser downloads the routines from the server and executes it. Client Functions

u Query processing from browser (client) to server –Browser send a web page request to the server –Server receive the page request and validate. Then, pass to the middleware –Middleware read the script, validate and execute it. Send SQL command to the DBMS, retrieves the info. And send the result back to the middleware –Server takes and send the page to the browser Server Functions

Web server interface u Web server provide standard interface to communicate with external program u Two common interfaces : –Application Programming Interface (API) (has dynamic link libraries, DLL), disadvantage is it is vendor and OS specific –Common Gateway Interface (CGI)

Internet / Intranet and its Security u Internet - a worldwide collection of interconnected computer network u Intranet – an internal corporate network, LAN or WAN u Benefits of intranet : –Ease of use –Open standard –Platform independence: Runs anywhere –Multiple data source –Uniform interface –Shorter development time

u Firewall – a software / hardware components that limits and control : –Data traffic to an organization’s database from the outside world –Data that are permitted to flow from an organization the outside world. Internet / Intranet and its Security

u END