Understanding Rocket U2 XML Features

March 7, 2018

This article reviews the XML capabilities within Rocket U2 UniData® and UniVerse®. Learn the various functions within the databases to develop robust applications that can communicate with any system using XML. Explore the U2 XDOM and XMAP APIs and how to produce XML documents from the database query engines. Examples are included.

Introduction

In today’s ever-changing business world, more and more developers are looking for ways to design and build applications that can communicate with a variety of third-party applications and services. Developers have always had a choice of development environments and tools, but with those choices came communication methods and protocols that required extensive coding to enable two distinct applications to communicate with one another.

A popular method of such communication is known as Electronic Data Interchange (EDI). EDI is the transfer of information between systems via such mediums as the Internet. A great many businesses adopted EDI to place orders, send invoices, and otherwise exchange information. As EDI became more and more popular, it eventually became known as the X12 standard, ratified by the American National Standards Institute (ANSI).

When EDI communications became commonplace, developers often had to enhance applications more than once to accommodate changes in how their companies did business with other companies. This became costly to businesses, requiring development resources to continuously maintain EDI-based applications. Businesses had to evolve to survive, and with that evolution came the increased need to update data exchange methods.

In 1986, the International Organization for Standardization developed and standardized a new system for defining information. This system is known as Standard Generalized Markup Language (SGML), and became the ISO 8879 standard. SGML is a complex system that specifies rules for tagging elements in a document, which can then be used for formatting information in various ways. With the growth of the Internet, another markup language became popular, fostering more interest in SGML, since this new markup language used SGML rules. This technology is known as HyperText Markup Language (HTML).

HTML allows the creation of specially formatted documents that support links to other documents and the embedding of graphic images, audio, and video files. Tools, known as Web browsers, were created to display this form of document. HTML uses special tags that define the content and layout of the document, which helps to create forms and other content-rich documents that make the World Wide Web what it is. As powerful as HTML has become, it is still not well-suited for data interchange between disparate systems.

Download this PDF to learn more including:

1. An overview of XML
2. U2 XML features
   1. Using UniQuery and RetrieVe to produce XML
   2. TOXML command
   3. TODB command
3. XML in U2 BASIC
   1. XDOM API
   2. XMAP API
   3. XMLExecute function
   4. U2 XML/DB tool
4. Programming examples
   1. U2 XMAP example (UniData)
   2. U2 XDOM example (UniVerse)
   3. U2 XDOMQuery example (UniVerse)
5. Summary