Oracle8i Application Developer's Guide - XML Release 3 (8.1.7) Part Number A86030-01 |
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Customizing Presentation with XML and XSQL: Flight Finder, 4 of 8

## How Flight Finder Works

Flight Finder queries the database for information about flights from one city to another, then returns the results in a format customized for your end-user's device. Built on Oracle8i, Flight Finder uses the following products and technologies:

- SQL, the standard for accessing business data

- Oracle XSQL Servlet, which processes queries defined in XSQL pages. XSQL pages are XML documents that contain SQL code. XSQL Servlet outputs the result set as XML.

- XSLT, which defines an open standard for transforming XML for target devices.

This chapter describes how Flight Finder application was implemented. You can use these techniques in any Web-based application that:

- Receives requests from any client device on the Web.

- Delivers database content to multiple devices.

- Writes input from multiple devices back to the database.

Figure 8-1 shows how Flight Finder works.

#### Figure 8-1 XML Flight Finder

1. Using any supported client device, an end-user fills out a form to specify a starting point and a destination. The form's source code specifies an XSQL page to execute when the end-user submits the form.

2. The Web server invokes the XSQL Servlet with an XSQL Page.

3. The XSQL Servlet parses the XSQL page and queries the database.

4. The database returns the query results, which the XSQL Servlet converts to an XML document.

5. The XSQL Servlet transforms the XML by applying an XSL stylesheet appropriate for the end-user's client device.

6. The Web server returns the customized document to the client.

With Oracle8i, you can run Oracle XML components and applications built with them inside the database. For devices and applications that require a smaller database footprint, you can use Oracle8i Lite to store and retrieve XML data. You can also run these components on a middle tier such as Oracle Internet Application Server 8i, or on the client.

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