XML Authority Ends Waiting Game for Schema Developers

July 1, 1999

Dale Dougherty

There are standards and there are products, and for the rapidly changing Web, these often seem like parallel worlds rather than convergent paths. From the moment XML emerged as a W3C Recommendation, those who were in a position to adopt XML began wondering what to do about DTD development. There were rumors that something very new was coming, something called schemas that would obsolete DTDs. First a number of vendors announced submissions, some hastily prepared. Then, because so many saw themselves as stakeholders in a new standard, there was inevitably some political scheming to get there first. After a few fits and starts, the W3C approved a working group and in May, that group produced the XML Schemas draft.

Meanwhile, those in the vanguard of XML development have had three options: start developing DTDs; hold off on schema work until a standard has been set; or adopt the vendor-specific proposal that comes closest to their needs. If you are trying to move ahead, playing the waiting game is risky. However, taking a bold step forward might look foolish in several months.

Given a new schema development tool from Extensibility called XML Authority, there might be a way to make progress today while keeping your options open for the future. XML Authority practically creates a new kind of application category -- standards-ware. What defines this category is not simply that these products support standards; they support the oft-quoted remark that what's great about standards is that there are so many to choose from.

XML Authority regards DTDs and each of the different schema proposals as essentially the same from the developer's point of view. They use different syntax and there are some differences in features but there is a lot in common. Developers can use XML Authority as a consistent interface for building schemas, regardless of whether you want the result saved as a DTD, or in any of the prevalent schema proposals. This allows the developer to be a standards pragmatist and start getting some useful work done today.

A schema defines a vocabulary of elements and expresses a set of relationships or rules that describe the structure of documents used in an application. A schema can be used to validate the structure of an XML document. Perhaps just as importantly, it provides essential documentation for users who are creating documents as well as application developers who are concerned with processing that information.

XML Authority is a visual editing environment for creating and testing schemas. It is also good for viewing existing DTDs or other schema examples in a consistent way. For many of us, the syntax of DTDs can be confusing and awkward, and while a visual interface doesn't necessarily spare you from knowing the underlying syntax, it allows you a higher level, interpreted view of the structure you are creating.

 Figure 1. Screen shot of XML Authority 1.0.
In the top half of the window, the schema is represented visually as a tree. In the bottom half, the schema can be edited in a columnar display.
 Screen Shot of XML Authority

XML Authority 1.0 is available for Windows. It costs $99 and you can download a 10-day trial version. For more information about XML Authority, visit the Extensibility web site. will be taking a more in-depth look at this product in the future.