Accessing and Manipulating XML Data in Microsoft .NET Framework

Summary

·XML or Extensible Markup Language describes document structures using markup tags '<' and '>'. A well-formed XML document should contain a start tag and an end tag. Unlike HTML tags, XML tags are case-sensitive.

·An XML document is a well-formed text-based data and considered as a meta-language that can easily be edited and created with any text editor. The XML data comprises of both human-readable data and descriptions of that data, and contains text-based XML files.

·The XML Document Object Model commonly known as XML DOM is a representation of XML document in memory. The DOM class does the work of reading, writing, and manipulating an XML document.

·The XmlDocument object derived from the XmlNode class represents the root node or the document node. The XmlDocument object consists of Load, LoadXml and Save methods that loads and saves XML documents.

·The XmlTextReader class derived from the XmlReader class implements the methods defined by the XmlReader class. The XmlValidating Reader is another class derived from the XmlReader class facilitates to read XML data and supports the document type definition (DTD) or schema validation.

·XML Path or XPath language is a query language for finding information in an XML document. XPath also contains built-in standard functions to manipulate string, numeric, and boolean values, and to manipulate sequences and nodes.

·The structure of XML documents is based on rules that are specified in an XML Schema Definition (XSD) file also known as an XML Schema. An XSD file consists of the definitions of elements, attributes, and data types.

·The XML Schema Object Model (SOM) derived from the System.Xml.Schema namespace consists of a set of classes that read the schema definition from a file and also create the schema definition files programmatically.

·The XML SOM is also used to read and write XSD language schemas from files or other sources using the XmlTextReader, XmlTextWriter, and XmlSchema classes.

·The XmlValidatingReader class derived from the XmlReader class provides the document type definition (DTD), the XML Data Reduced (XDR), and the XSD schema validation services for the validation of an XML document or a fragment of an XML document.

·A DataSet stores data obtained from a data source such as a relational database or an XML document. A DataSet can either be in form typed or untyped.

·ADO.NET writes the DataSet data as a DiffGram, which means that both the original and current versions of the rows are included. A DiffGram can be represented in the XML format and is used to store and preserve all versions of the data.