Y at Company X can take on a number of different XML document patterns.
Any of the three examples above can be considered to be proper XML documents.
In addition, it was written using a dialect of SGML that runs completely counter to the current XML specification.
It was for these reasons that the XML Schema Definition Language, or XSD specification, was ultimately developed.
Traditionally, DTD has been the standard for XML schema definition; however, XML usage has expanded dramatically in core application systems, being tailored for a wide range of purposes for which DTD is not fully capable of supporting.
Given this development, the W3C recommended "XML Schema" as a schema definition language to replace DTD.
When validation completes, you will be presented with a validation results dialog, and any problems found will be shown in the Problems view.
With XML Schemas, the sender can describe the data in a way that the receiver will understand. However, an XML element with a data type like this: Even if documents are well-formed they can still contain errors, and those errors can have serious consequences. An XML document without a specific, well-defined structure is just an ad-hoc set of tags.Until relatively recently, though, one language to describe those tags, Document Type Definitions or DTDs, lacked the ability to specify information about tags as holders of data.The easier solution, and the one discussed in this article, is to create an instance of the XML document, then use schema production tools to generate a schema that is valid for that instance.In this case, the more complete the instance is to your final requirements, the more the tools can do to build the schema from it.