The document discusses using the DOM API to read, write, and manipulate XML data in .NET applications. It describes how to load an XML document into memory using the XmlDocument class, access and traverse the DOM tree, create new nodes, insert and delete nodes, and calculate values from the XML data. An example problem demonstrates adding new data and modifying an XML file based on database records using the DOM.

1. Developing Database Applications Using ADO.NET and XML
Objectives
In this session, you will learn to:
Read and write XML data using DOM API
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2. Developing Database Applications Using ADO.NET and XML
Processing XML Data Using DOM
Many applications need the ability to:
Read an entire XML document into memory
Access XML content in any order
Modify the XML content in memory
The XML Document Object Model (DOM) is an Application
Programming Interface (API) that provides full read-write
random-access capabilities for reading and writing XML
data.
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3. Developing Database Applications Using ADO.NET and XML
Reading XML Data into DOM
• You can load an XML document into a DOM tree using the
XmlDocument class.
• The XmlDocument class provides the following two methods
to load an XML document into memory:
 Load(): This method loads XML data from a stream, a string, an
XmlReader, or a TextReader.
XmlDocument doc = new XmlDocument();
XmlTextReader reader = new
XmlTextReader("C:books.xml");
reader.Read();
doc.Load(reader);
 LoadXml(): This method is used load an XML file from a string.
XmlDocument doc = new XmlDocument();
doc.LoadXml(("<BOOKDETAILS><BOOK><BOOKNAME>The
DaVinci Code</BOOKNAME><AUTHOR>Dan
Brown</AUTHOR></BOOK></BOOKDETAILS>"));
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4. Developing Database Applications Using ADO.NET and XML
Reading XML Data into DOM (Contd.)
Accessing child nodes:
 The XmlNode.ChildNodes property is an XmlNodeList that
contains all the child nodes of the node.
 Some of the other properties of the XmlNode class are described
in the following table.
Property Description
FirstChild It is used to access the first child under the reference node.
LastChild It is used to access the last child under the reference node.
NextSibling It is used to access the node immediately next to the reference
node.
PreviousSibling It is used to access the node immediately preceding the reference
node.
ParentNode It is used to access the parent node of the reference node.
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5. Developing Database Applications Using ADO.NET and XML
Writing XML Data from DOM
Creating new nodes in the DOM tree:
 You can create new nodes using the Create<Node_Type>
method of XmlDocument, where <Node_Type> is the type of
node.
 After creating the new nodes, you need to insert them into the
DOM tree using the following methods.
Property Description
InsertBefore() It is used to insert a node before the referenced node.
InsertAfter() It is used to insert a node after the referenced node.
AppendChild() It is used to add the node to the end of all the child nodes for the given node.
PrependChild() It is used to add the node to the beginning of all the child nodes for the given
node.
Append() It is used to add an XmlAttribute node to the end of the attribute
collection that is associated with an element.
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6. Developing Database Applications Using ADO.NET and XML
Writing XML Data from DOM (Contd.)
 Creating an XML Declaration: The XmlDocument class has
a CreateXmlDeclaration()method that is used for
creating XML declarations. This class has the following
parameters:
 Version: The version should be 1.0.
 Encoding: Encoding is used when you save the XmlDocument
to a file or stream. Encoding should be set to a string supported
by the Encoding class, as otherwise, the Save() method will
not work.
 Standalone: The value is either yes or no. If null is passed,
the Save() method does not write a standalone attribute in the
XML declaration.
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7. Developing Database Applications Using ADO.NET and XML
Writing XML Data from DOM (Contd.)
 Creating elements: The CreateElement() method is used for
creating XML elements.
Consider the following XML File called books.xml:
<BOOK BOOKID='B001'>
<BOOKNAME>The DaVinci Code</BOOKNAME>
<AUTHOR>Dan Brown</AUTHOR>
</BOOK>
Consider the following code snippet:
XmlElement element =
doc.CreateElement("PRICE"); Name of the element
XmlText text =
doc.CreateTextNode("20"); Value of the element
On executing the preceding code, the books.xml becomes:
<BOOK BOOKID='B001'>
<BOOKNAME>The DaVinci Code</BOOKNAME>
<AUTHOR>Dan Brown</AUTHOR>
<PRICE>20</PRICE>
</BOOK>
Ver. 1.0 Session 13 Slide 7 of 10

8. Developing Database Applications Using ADO.NET and XML
Writing XML Data from DOM (Contd.)
Deleting nodes from the DOM tree
 You can delete nodes from a DOM tree by using the
RemoveChild() method.
Consider the following XML File called books.xml:
<BOOK BOOKID='B001'>
<BOOKNAME>The DaVinci Code</BOOKNAME>
<AUTHOR>Dan Brown</AUTHOR>
</BOOK>
Get reference to the first
Consider the following code snippet:
BOOK element.
XmlNode node = doc is an object of
doc.DocumentElement.FirstChild; XmlDocument.
node.RemoveChild(node.FirstChild); Remove the BOOKNAME
element.
On executing the preceding code, the books.xml becomes:
<BOOK BOOKID='B001'>
<AUTHOR>Dan Brown</AUTHOR>
</BOOK>
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9. Developing Database Applications Using ADO.NET and XML
Demo: Manipulating XML Data Using DOM
Problem Statement:
 Peter is a developer in Tebisco. He has to create an
application that will transfer the data stored in the JobFair table
into an XML file called JobFair.xml. In addition, he has been
assigned with the following tasks:
Calculate the total number of job fairs held
Add details of a new job fair to the XML file. This new fair has the
following details:
cJobFairCode: 0006
vLocation: 15, Madison Street, Alabama
vJobFairCompany: MoreJobs Ltd.
mFee: 25
dFairDate: 2006-11-10
You need to develop an application that would perform these
tasks for Peter.
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10. Developing Database Applications Using ADO.NET and XML
Summary
In this session, you will learn to:
 While the XmlReader and XmlWriter classes give you serial
access to an XML document, the DOM API gives you random
access to any element or attribute in the XML document.
 In the .NET Framework, NamedNodeMap is implemented by
the XmlNamedNodeMap class, and NodeList is implemented
by the XmlNodeList class.
 An XML document can be created by using the XmlDocument
class.
Ver. 1.0 Session 13 Slide 10 of 10