Derik Whittaker : Mini-Series

XLinq'n in the new world - Speed comparison with Xml/XPath

Derik Whittaker — Wed, 14 May 2008 15:02:22 GMT

Originally this series was meant to be titled 'Any thing you can do I can do better', but to be honest after writing the Xml/XPath examples I realized the XLinq is really no better per say than Xml/XPath. However, what XLinq does bring to the table that Xml/XPath does not:

Does not need to use the XPath query syntax
Reads like English (mostly) when creating queries
Lower barrier to entry for someone new to Xml (my opinion)

For Part 1 of this series check here
For Part 2 of this series check here
For Part 3 of this series check here

In Part 4 of this little mini-series we will examine the speed differences between XLinq and Xml/XPath.

Before I get started I will show you a sample of the XML document I am using. The sample document I am using today is 5.25mb in size.

<?xml version='1.0'?>
<root>
<system>
    <list>
      <subscribers>
        <subscriber Type="Random">
          <id>63425813</id>
          <Email__Address>FakeAddress@comcast.net</Email__Address>
          <EmailType>HTML</EmailType>
          <Status>InActive</Status>
          <First__Name>RAY</First__Name>
          <Last__Name>Bob</Last__Name>
          <PIN__Code>NaN</PIN__Code>
          <PIPIN>33232</PIPIN>
          <UID>418444</UID>
          <ProgNum>0</ProgNum>
          <Title />
          <Username />
          <Password />
        </subscriber>
      </subscribers>
    </list>
    <list>
      <subscribers>
          <subscriber>
          <id>1271728821</id>
          <Email__Address>FakeAddress@yahoo.com</Email__Address>
          <EmailType>HTML</EmailType>
          <Status>InActive</Status>
          <First__Name>JOHN</First__Name>
          <Last__Name>Foo</Last__Name>
          <PIN__Code>NaN</PIN__Code>
          <PIPIN>1254512</PIPIN>
          <UID>1033488</UID>
          <ProgNum />
          <Title />
          <Username />
          <Password />
        </subscriber>
      </subscribers>
    </list>
</system>
</root>

Example 1 - Loading a XML document from Resource Stream

There is no real code to show here, but I do have some speed numbers to chat about. I ran my test 2 times. The first time I loaded into a XLinq object first then into an XmlDocument object and for the second run, I swapped the order.

As it turns out the first document to load each time is slower, but you can get a look at the speed difference by looking at the delta between each load time.

Load Time

XmlDocument	515.00	327.72	187.27 (Delta)
XLinq	358.94	546.2135	187.27 (Delta)

By looking at the above, there is no real speed difference, which I expected. (Time above is in milliseconds)

Example 2 - Finding a Unique value in the Xml Document

For this example I decided to try to find a single node inside my larger xml file. In order to try to get good sample I ran each test 5 times and the times below are the average of all those runs

Run time (5 run avg)

XLinq	44.62
Xml/XPath	125.65

I have to say that I was kinda surprised by the results. I figured that the Xml/XPath way would be a little faster, but turns out it is 3 times slower. (Time above is in milliseconds). ** NOTE *** The times above do NOT include the time needed to load the XML document into the correct object model.

From the information in this mini-series i would conclude that if you need to do any type of XML reading/manipulation/creation I would make the jump over to using XLinq as your preferred way of doing so.

Till next time,

XLinq'n in the new world - Structure Modification comparisons with Xml/XPath

Derik Whittaker — Wed, 14 May 2008 12:21:19 GMT

Does not need to use the XPath query syntax
Reads like English (mostly) when creating queries
Lower barrier to entry for someone new to Xml (my opinion)

For Part 1 of this series check here
For Part 2 of this series check here

In Part 3 of this little mini series we will examine some common data creation scenario's and how XLinq's syntax compares to that of standard Xml/XPath access. In general will we review how to modify the structure of an existing Xml document.

Before I get started I will show you a sample of the XML document I am using.

Example 1 - Adding a New Node w/ Element

via Xml/XPath

// notice the @ is missing on the status -- this is how u search a node
XmlDocument xmlDocument = XmlHelper.GetRawSnippetAsXmlDocument();
XmlNodeList xmlNodeList = xmlDocument.SelectNodes( "//list" );

foreach ( XmlElement element in xmlNodeList )
{
    XmlNode newNode = xmlDocument.CreateNode( XmlNodeType.Element, "NewElement", string.Empty );
    XmlAttribute nodeAttribute = xmlDocument.CreateAttribute( "MyAttribute" );
    nodeAttribute.Value = "MyValue";

    newNode.Attributes.Append( nodeAttribute );

    element.AppendChild( newNode );
}

Via XLinq

XDocument xDocument = XmlHelper.GetRawSnippetAsXDocument();

IEnumerable item = from doc in xDocument.Descendants( "list" )
                             select doc;

foreach ( XElement xElement in item )
{
    xElement.Add( new XElement( "NewElement",
                                new XAttribute( "MyAttribute", "MyValue" ),
                                new XElement( "ChildElement", "ChildValue")) );
}

//ChildValue

One of the big differences you will notice when trying to add nodes/elements to an existing Xml doc with XLinq vs. Xml/XPath is the that with XLinq it is more 'fluent' then with Xml/XPath. To add nodes/elements with Xml/XPath you need to create the nodes/elements via the XMLdocument object.

Example 2 - Deleting and Node w/ Elements

via Xml/XPath

// notice the @ is missing on the status -- this is how u search a node
XmlDocument xmlDocument = XmlHelper.GetRawSnippetAsXmlDocument();
XmlNodeList xmlNodeList = xmlDocument.SelectNodes( "//subscribers/subscriber[Status='InActive']" );

foreach ( XmlElement element in xmlNodeList )
{
    element.RemoveAll();
}

Via XLinq

XDocument xDocument = XmlHelper.GetRawSnippetAsXDocument();

IEnumerable< XElement > item = from doc in xDocument.Descendants( "subscriber" )
                               let status = (string) doc.Element( "Status" )
                               where status == "InActive"
                               select doc;

foreach ( XElement xElement in item )
{
    xElement.Remove();
}

Besides the way you navigate to the node/element you would like to remove the syntax to delete/remove the nodes are really no different. But, again with XLinq you do not need to know XPath in order to navigate to the correct location in the document.

Well, this pretty much wraps up my little mini-series on XLinq'n in the new world. I hope that in the past 3 posts you have learned a little about how to use XLinq and how it differs from Xml/XPath.

Till next time,

XLinq'n in the new world - Data manipulation comparisons with Xml/XPath

Derik Whittaker — Tue, 13 May 2008 10:37:51 GMT

Does not need to use the XPath query syntax
Reads like English (mostly) when creating queries
Lower barrier to entry for someone new to Xml (my opinion)

For Part 1 of this series check here

In Part 2 of this little mini series we will examine some common data manipulation scenario's and how XLinq's syntax compares to that of standard Xml/XPath access. In general will we review how do update the content of both elements and attributes in an XML document.

Before I get started I will show you a sample of the XML document I am using.

Example 1 - Updating Element Values

via Xml/XPath

// notice the @ is missing on the status -- this is how u search a node
XmlDocument xmlDocument = XmlHelper.GetRawSnippetAsXmlDocument();
XmlNodeList xmlNodeList = xmlDocument.SelectNodes( "//subscribers/subscriber[Status='InActive']" );

// Attribute value before updates
// 
// 

foreach ( XmlElement element in xmlNodeList )
{
    // this will only set the value.  if the node does NOT exist you will get an exception.
    element.SelectSingleNode( "//Status" ).InnerText = "Active";
}

// Attribute values afterupdate
//

via XLinq

XDocument xDocument = XmlHelper.GetRawSnippetAsXDocument();

var item = from doc in xDocument.Descendants( "subscriber" )
           let status = ( string )doc.Element( "Status" )
           where status == "InActive"
           select doc;

// Attribute value before updates
// InActive

foreach ( XElement xElement in item )
{
    // this will set the value or create it if the element does not exist
    xElement.SetElementValue( "Status", "Active" );

    // Another option is to go after the element directly, but this requires a 
    //  null check first
    if ( xElement.Element( "Status" ) != null )
    {
        xElement.Element( "Status" ).SetValue( "Active" );
    }

}

// Attribute values after update
// Active

As you can see the differences between using XLinq and Xml/XPath for updating elements is not the big. However, again you have to know/understand how to use XPath to find your nodes. There is ONE thing you need to be aware of though. When trying to update an element via XPath the element MUST exist. If it does not you will get a runtime exception. With XLinq there is a way to do this and not have to worry about that. To me that is pretty nice.

Example 2 - Updating Attribute Values

via Xml/XPath

// notice the @ is missing on the status -- this is how u search a node
XmlDocument xmlDocument = XmlHelper.GetRawSnippetAsXmlDocument();
XmlNodeList xmlNodeList = xmlDocument.SelectNodes( "//subscribers/subscriber[Status='InActive']" );

// Attribute value before updates
// 

foreach ( XmlElement element in xmlNodeList )
{
    // this will set the value or create it if the attribute does not exist
    element.SetAttribute( "Type", "SomeValue" );
}

// Attribute values afterupdate
//

via XLinq

XDocument xDocument = XmlHelper.GetRawSnippetAsXDocument();

var item = from doc in xDocument.Descendants( "subscriber" )
           let status = ( string )doc.Element( "Status" )
           where status == "InActive"
           select doc;

// Attribute value before updates
// 

foreach ( XElement xElement in item )
{
    // this will set the value or create it if the attribute does not exist
    xElement.SetAttributeValue( "Type", "MyValue" );

    // Another option is to go after the attribute directly, but this requires a 
    //  null check first
    if ( xElement.Attribute( "Type" ) != null )
    {
        xElement.Attribute( "Type" ).SetValue( "SomeValue" );
    }
    
}

// Attribute values afterupdate
//

Above shows you that updating attributes are almost identical and in this case there is no need to know/understand XPath in order to select the single node you are trying to update.

Well, above I have shown you a few simple examples that compare Xml/Path to XLinq, I hope you find this useful. The next post will compare how to modify the structure of a document using the both Xml/XPath and XLinq.

Till next time,

XLinq'n in the new world - Data access comparisons with Xml/XPath

Derik Whittaker — Mon, 12 May 2008 10:15:22 GMT

Does not need to use the XPath query syntax
Reads like English (mostly) when creating queries
Lower barrier to entry for someone new to Xml (my opinion)

In Part 1 of this little mini series we will examine some common data access scenario's and how XLinq's syntax compares to that of standard Xml/XPath access.

Before I get started I will show you a sample of the XML document I am using.

Example 1 - Simple data access

via Xml/XPath

XmlDocument xmlDocument = XmlHelper.GetRawSnippetAsXmlDocument();

// notice the @ is on the status -- this is how u search a element
Int32 listCount = xmlDocument.SelectNodes( "//list" ).Count;
Int32 subscribersCount = xmlDocument.SelectNodes( "//subscriber[@Type='Random']" ).Count;

via XLinq

XDocument xDocument = XmlHelper.GetRawSnippetAsXDocument();

Int32 listCount = xDocument.Descendants( "list" ).Count();
Int32 subscribersCount = xDocument.Descendants( "subscriber" ).Attributes( "Type" ).Where( e => e.Value == "Random" ).Count();

As you can see both examples are pretty light on the code and are pretty straight forward. This is one case where the new XLinq syntax is really no better/simpler then the Xml/XPath syntax. The issue with the XPath syntax is that

Example 2 - Get a list of nodes that match our search criteria

via Xml/Xpath

// notice the @ is missing on the status -- this is how u search a node
XmlDocument xmlDocument = XmlHelper.GetRawSnippetAsXmlDocument();
XmlNodeList xmlNodeList = xmlDocument.SelectNodes( "//subscribers/subscriber[Status='InActive']" );

foreach ( XmlElement element in xmlNodeList )
{
    var id = element.SelectSingleNode( "//id" ).InnerText;
    var type = element.Attributes[ "Type" ].Value;
}

via XLinq

XDocument xDocument = XmlHelper.GetRawSnippetAsXDocument();

var item = from doc in xDocument.Descendants( "subscriber" )
           let status = (string)doc.Element( "Status" )
           where status == "InActive"
           select doc;

foreach ( XElement xElement in item )
{
    var id = xElement.Element( "id" ).Value;
    var type = xElement.Attribute( "Type" ).Value;
}

Now here is an example where I think the XLinq syntax is cleaner and easier to understand. There is no need to know or understand the XPath syntax, which can be a pain to learn. Also here you see how XLinq looks a lot like standard SQL syntax and should be familiar to most developers.

Well, above I have shown you a few simple examples that compare Xml/Path to XLinq, I hope you find this useful. The next post will compare how to update/add data to a document using the both Xml/XPath and XLinq.

Till next time,