JDBC Connect User's Guide

CHAPTER 1

Welcome to exteNd Composer and JDBC

 
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Before You Begin

Welcome to the Novell exteNd JDBC Connect User's Guide. This Guide is a companion to the exteNd Composer User's Guide, which details how to use all the features of Composer except for the Connect Component Editors. So, if you haven't looked at the Composer User's Guide yet, please familiarize yourself with it before using this Guide.

exteNd Composer provides separate Component Editors for each Connect, such as the JDBC connector. The special features of each component editor are described in separate Guides like this one.

If you have been using exteNd Composer, and are familiar with the core component editor (the XML Map Component Editor), then this Guide should get you started with the JDBC Component Editor.

NOTE:   To be successful with this Component Editor, you must be familiar with writing and constructing SQL statements.

 
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About exteNd Connects

Novell exteNd is built upon a simple hub and spoke architecture. The hub is a robust XML transformation engine that accepts XML documents, processes the documents, and returns an XML document. The spokes or Connects are plug-in modules that "XML enable" sources of data that are not XML-aware. These data sources can be anything from legacy COBOL / VSAM managed information to Message Queues to HTML pages. exteNd Connects can be categorized by the integration strategy each one employs to XML enable an information source. The integration strategies are a reflection of the major divisions used in modern systems designs for Internet based computing architectures. Depending on your B2Bi needs, exteNd can integrate your business systems at the User Interface, Program Logic, and/or Data levels.

 
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What is JDBC?

JDBC is a Java-based API (Application Programming Interface) for executing SQL statements. While often mistaken as an acronym meaning "Java Database Connectivity," JDBC is in fact not an acronym at all, but a trademarked name. JDBC consists of a set of classes and interfaces written in the Java programming language that allows you to write one program to access different databases such as Oracle, Sybase, Informix, etc., rather than needing to write a separate program for each one.

You can write a single program using the JDBC API and the program is able to send SQL statements to the appropriate database. And since the application is written in the Java programming language, there is no need to write different applications to run on different platforms. The combination of Java and JDBC lets you write it once and run it anywhere, as the following illustration shows.

 
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What Does JDBC Do?

JDBC makes it possible to do the following:

JDBC is a low-level interface used to call SQL commands directly. It is integrated into Composer to interface between components and databases, allowing the program to establish connections with the databases, send the SQL statements, and process the results. Composer provides tools that enable visual construction of the necessary SQL commands.

 
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About exteNd's JDBC Component

Much like the XML Map Component, the JDBC Component is designed to map, transform, and transfer data between two different XML templates (i.e., request and response XML documents). However, it is specialized to make a connection to a database, process SQL statements against the database using elements from a Message Part within the query, and then map the results of the query to a Part.

A JDBC Component can perform simple data manipulations, such as mapping and transferring data from one XML document to another, or from an XML document to a database table. It can also perform sophisticated manipulations, such as requesting data from disparate databases, transforming data from and to one or more documents, executing SQL transactions against the database, and even transforming the documents themselves. Like an XML Map Component, the JDBC Component can process XSL, send mail, and post and receive XML documents using the HTTP protocol.

The JDBC Connect uses exteNd Composer as the backplane for XML-based data interactions, making it possible to reach into databases at runtime (and design time). Using exteNd Composer, you can assemble Action Models within a JDBC Component to carry out sophisticated data transformations, using HTTP (optionally) as a transport mechanism. Live database connections are available at design time, so that you can edit and debug SQL queries as part of the design process.

 
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What Kinds of Applications Can You Build Using the JDBC Component Editor?

You can build any business-to-business application that needs to push data into or pull data from a JDBC-accessible data store and uses XML as the interchange format. For example, you can write an application that retrieves the description, picture and price of a product from a database and displays it in the user's browser. If the information resides in two or more databases, you can merge the information from separate databases before displaying it to the user.



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