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public. ConText offers a series of PL/SQL packages that allows a user to quickly create an index on all the resumes, which now, thanks to ConText, are stored directly in the database. To create this index, the ConText DBA would use the following two packages:

 SQL> EXECUTE ctx_ddl.create_policy(`RESUME_POLICY', EMP.RESUME); 

and

 SQL> EXECUTE ctx_ddl.create_index(`RESUME_POLICY'); 

After this task, by using SQL, anyone could search for a resume with the phrase "master wielder" in it, with the simple command:

 select name from EMP where contains(RESUME, `MASTER WIELDER') > 0; 

The contains clause is similar to the SQL instr function, but is operating on an index of a text document created by ConText and does not search a simple string.

In Web design, the ConText option allows dynamic Web pages to bring up documents quickly from a database that does not need to be residing on the disk. This turns a complex document into just another object for the PL/SQL and HTML Web developers to deal with. They only need to pull the text out of the database with a Select statement if the user requests it. This cuts down on the security risk of exposing the document as a simple file on a public server and speeds up the process by using database indexes, natural language rules, and the multiple read/write features of the Oracle database.

If we really are going to take the NCA (network computing architecture) seriously, we must realize that one of the basic datatypes, or objects, that an NC of the future will request will be a text document. ConText now becomes an indispensable piece of the Oracle Universal Server. Relational databases should be able to store documents as easily as dates. There was nothing in the original writings of E. F. Codd that discouraged text to be a valid datatype. Now with the CORBA standard and network computing, text must be treated as just another object that can be requested by a client NC from an NC server that is linked to a RDBMS.

After this method becomes easier for people, searching with a word processor on a disk for that lost document will become obsolete and this methodology of document management will become a standard.

VRML

If you think HTML is a far cry from the William Gibson science fiction worlds where you can actually plug in your mind to the World Wide Web, maybe you're right. But don't worry. There are many people thinking along your lines. Because HTML can only translate simple graphics and pictures between you and your customer's browser, a new language called VRML has arisen. VRML stands for Virtual Reality Modeling Language. If you think this is some hacker's dream, beware. Both the Netscape and Microsoft Web browsers support VRML. You can embed VRML code in with your HTML code and give users access to more complex graphical objects.

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VRML is for handling virtual reality. Because reality for human beings is a 3D visual experience, VRML handles the nuances of 3D graphics. With 3D graphics, we are faced with objects that don't exist in 2D pictures. VRML handles objects such as cubes, cones, cylinders , and spheres. Along with the basic object, VRML allows for specifications for different types of lighting and rendering upon objects to make them appear three-dimensional.

VRML is an excellent tool for graphical and engineering applications. Because it assumes a 3D world, it uses the logical x, y, and z coordinates of 3D geometry.

The power of using coordinate geometry makes VRML an ideal language to publish the output of CAD/CAM tools or other geometric tools. For instance, if you were building a Web page for a real-estate company and wanted to display 3D renderings of each house for sale, VRML would be a logical choice if you already had this information in another computer-based format.

One of the key issues with VRML is converting 3D files from other formats to VRML. Some of the common formats that are being put up on the Web today are the following:

  • AOFF (*.geo) files
  • AutoCAD (*.dxf) files
  • 3D Studio (*.3ds) files
  • Neutral File Format (*.nff) files
  • RAW (*.raw) files
  • TPOLY (*.tpoly) files

VRML filenames end in .wrl. They are embedded in a Web page with HTML. After you have converted a 3D image to a .wrl format, there are two ways to embed the world (that's actually the syntax) that you have created. One way is to use an HTML frame, like this:

 <FRAME SRC="reality.wrl" NAME="vframe1"> 

The second way is to embed the complete picture in a page, unframed, like this:

 <EMBED SRC="reality.wrl" WIDTH=432 HEIGHT=432> 

The first drawback with VRML in Web publishing is the narrow bandwidth that most Web surfers bring with them to the beach in the form of their modems and telephone hookups. Even transmitting simple graphics over these relays slows down the presentation to the user. VRML being downloaded by a browser through a modem is even slower.

The second drawback that you will face when you enter this brave new world is that these more complex objects look different with different browsers. Small differences in x, y, and z coordinate placement and/or shading can make a big difference when translated by two different browsers. Another problem with translation is that original files, such as CAD files, when converted to VRML using a conversion program, will look different depending on the conversion program. Sometimes engineers , artists , and scientists are disappointed when their perfect world is poorly converted to a .vrl file.

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NCA and VRML

The good news for VRML addicts is the Oracle NCA architecture. With a common architecture for corporate intranets , the problem of pushing VRML over modem lines and the World Wide Web disappears. Today many companies are using VRML in conjunction with languages such as Java and Perl.

For instance, in a network computing environment, with users running NCs off of a fast NC server, the network bandwidth of a corporate LAN or WAN is much faster than with a user out on the Web. Complex graphical objects and 3D rendering can take place quickly with the new NC machines, which are designed to request complex objects from a Web server. The Web servers, such as Oracle's Web server and Oracle8, are being designed with the knowledge that data in this environment will include complex objects like VRML. There is no reason that .vrl files will not translate into a common datatype, like a string now does, for the databases of the future.

With VRML as the standard for 3D objects in the world of network computers, people will start using new CAD and graphical rendering tools that will all be in the same format. VRML hopefully will become the new standard for software that does complex 3D calculations. Today these expensive rendering and design tools save their work using a number of different non-compatible formats.

Possibly in the future, when the Internet is linked to us by satellite and transmission speeds are much faster, VRML will became the expected tool to impress your audience as you publish Web pages in the twenty-first century. For now though, in the world of Web publishing, this language should be used only where it is needed because it is more resource- intensive . Expect to spend more time in the creation, integration, and maintenance of Web sites that utilize VRML.

Summary

If you have gone through this chapter, you have published your first Web page and used HTML. It is probably simpler than you thought it would be. As you can see, though, what is most important is clear design when you put information on the Web, not a lot of flash. It is also important that your Web site be fast and secure, and for that, a tool such as Oracle's Web server will allow you to reach more Web surfers and supply them with information faster. All Web sites are really databases of information, which is why Oracle's Web products provide obvious solutions to the problems of large-scale Web publishing and information transfer.

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Oracle Unleashed
Oracle Development Unleashed (3rd Edition)
ISBN: 0672315750
EAN: 2147483647
Year: 1997
Pages: 391

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