Dynamic Web databases implemented by Oracle components
Dynamic Web databases implemented by Oracle components
The ORACLE tutorial is: Implementing a dynamic Web database using the Oracle component. [Abstract] This article briefly introduces the basic methods for implementing Web databases, and discusses the basic methods for implementing dynamic Web by using one of the Oracle server options WebServer combined with PL/SQL and related built-in packages, A simple example is provided.
With the development of computer interconnection networks, Internet is becoming one of the main ways to exchange information around the world. As an important part of the Internet, global information network WWW (World Wide Web) Organizes information in the form of HTML and integrates and transmits various information in the form of hyperlink. It has a friendly interface, simple operations and other features, users can directly use a Web browser for convenient browsing and querying of various information. Therefore, as a window for organizations and enterprises to display information, the information and functions provided by Web servers directly affect their own images and customer visits.
In traditional Web servers, text and other information are stored and managed in the form of files, and the Web pages provided to users' browsers are mostly static. When a user enters the URL of an HTML document in a browser, the user accesses a file on the WebServer, it changes the content only when a Network Administrator places a new file with the same name on the Web server. With the expansion of WWW application fields, static Web pages are increasingly unable to meet the dynamic, real-time and interactive requirements of Information Services. This requires the combination of database technology and WWW, to achieve efficient access to data resources.
1. Use Oracle WebServer to build Web database applications
Oracle 8 Server is a complete information management environment. It is a storage space for a large amount of data and provides users with quick access to the data. It supports the C/S structure for distributed processing and Web computing. WebServer, one of its server options, provides powerful functions for Web database applications.
Generally, Web database applications can provide CGI, APIs, and other middleware on the WebServer end to connect to WebServer and DB Server, or allow users to download and run related applications to the client through a Web browser, access the database directly on the client, such as Java Applet, Active X, and Plug-in. This article describes how to use PL/SQL provided by Oracle 8 and its powerful built-in package to write programs for Dynamic Web applications. It is developed using middleware. Middleware manages communication between WebServer and DBServer and provides application services. It can directly call external programs or script code to access the database. Therefore, it can provide dynamic HTML pages related to the database, or execute the user query, format the query result into an HTML page, and then return it to the user's browser through WebServer. The general structure is as follows:
Web browsers → Internet → Web Server → CGI/API → Oracle DB Server
2. PL/SQL
Oracle supports a process processing language PL/SQL starting with version 6 and uses it as the standard programming language for all Oracle tools, thus, all process components can be implemented in Oracle Server products. PL/SQL can be used to implement the following important functions:
Stored procedures, that is, programs (or code segments) stored in Oracle databases and specific important work for your organization;
Database triggers, that is, the Code stored in the database, can be triggered by events generated by the application;
Package, that is, the code that combines multiple processes as a single program unit is stored in the database.
The built-in packages are pre-generated and stored in the database, and can be called in PL/SQL code blocks to pass parameters as needed. It can directly output the results to the terminal window, read and write data directly from the operating system file, and execute dynamic SQL and other functions. Commonly used such as HTP, HTF, OWA-UTIL, etc. The following uses an instance of dynamic online score query to describe its application in dynamic Web.
