Validating xml net
Pattern elements allow the user to group schema constraints logically.Some examples of logical groupings are: Text Only Elements, Valid Root Element, Check for ID Attribute. They may also have a attribute that refers to a URL for user documentation of the schema.XML schemas are necessary for communicating the structure of an XML document type to a machine. A person can easily interpret and understand both XML instances from the words used to describe their components.A person can verify if the documents adhere to a set conventions about how vehicle elements should be used.Consider the following XML: If one constraint on such a document is that a short Story element may only contain an author attribute if it isn't the child of anthology element, it wouldn't be possible to represent that constraint in a DTD.These DTD handicaps aren't going unnoticed, and the W3C is presently developing an XML Schema language (currently a W3C Candidate Recommendation) that is more expressive and powerful than DTDs.
In this article I show how to do the latter and assume the reader is at least familiar with XML 1.0, DTDs, XSLT, and XPath.Once a document is identified as belonging to a class of documents, many assumptions about its structure can be made.DTDs were the first standard mechanism for XML validation, and for all practical purposes still are.I've found Schematron to be the most promising of these.Schematron, created by Rick Jelliffe, defines a set of rules and checks that are applied to an XML instance.