How to insert and query nodes?

[=?Utf-8?B?SmFzb25UODA=?=]

Hi all,

I need to use XML to store some log data and then query that data. I'm
struggling with the right terminology, which is hindering my ability to
successfully search for a solution. Thanks in advance for your help!

Two questions:
1. In VB.NET, how can I append new "Log" record to a "Site" record?
2. How can I query all of "Log" records in a single "Site" for an average
"ResponseTime"?

------------------------------

<?xml version="1.0" standalone="yes" ?>
<Sites>
<Site Host="www.mysite1.com" IP="1.1.1.1" />
<Site Host="www.mysite2.com" IP="1.1.1.2" />
<Site Host="www.mysite3.com" IP="1.1.1.3">
<Log Time="1/1/2008 12:00:00 AM" Status="Success" ResponseTime="10" />
<Log Time="1/1/2008 12:00:01 AM" Status="Failure" ResponseTime="10" />
</Site>
<Site Host="www.mysite4.com" IP="1.1.1.4">
<Log Time="1/1/2008 12:00:00 AM" Status="Success" ResponseTime="10" />
<Log Time="1/1/2008 12:00:01 AM" Status="Failure" ResponseTime="10" />
</Site>
</Sites>

[Martin Honnen]

JasonT80 wrote:

Two questions:
1. In VB.NET, how can I append new "Log" record to a "Site" record?

With .NET 1.x, 2.0 and 3.0 you would use System.Xml.XmlDocument e.g.
Dim doc As New XmlDocument()
doc.Load("file.xml")
Dim log As XmlElement = doc.CreateElement("Log")
log.SetAttribute("Time", "...")
log.SetAttribute("Status", "...")
doc.SelectSingleNode("Sites/Site[@Host =
'www.mysite1.com']").AppendChild(log)
doc.Save("file.xml")

With .NET 3.5 you would use LINQ to XML. Let us know whether you use
that version and need sample code.

2. How can I query all of "Log" records in a single "Site" for an average
"ResponseTime"?

A solutuon again depends on whether you can use LINQ to XML so please
let us know which version of the .NET framework you use/want to use.

--

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/

[=?Utf-8?B?SmFzb25UODA=?=]

The environment has only .NET 2.0. Thanks for the help!

--
Jasont80
"Martin Honnen" wrote:

JasonT80 wrote:

Two questions:
1. In VB.NET, how can I append new "Log" record to a "Site" record?

With .NET 1.x, 2.0 and 3.0 you would use System.Xml.XmlDocument e.g.
Dim doc As New XmlDocument()
doc.Load("file.xml")
Dim log As XmlElement = doc.CreateElement("Log")
log.SetAttribute("Time", "...")
log.SetAttribute("Status", "...")
doc.SelectSingleNode("Sites/Site[@Host =
'www.mysite1.com']").AppendChild(log)
doc.Save("file.xml")

With .NET 3.5 you would use LINQ to XML. Let us know whether you use
that version and need sample code.

2. How can I query all of "Log" records in a single "Site" for an average
"ResponseTime"?

A solutuon again depends on whether you can use LINQ to XML so please
let us know which version of the .NET framework you use/want to use.

--

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/

[Martin Honnen]

JasonT80 wrote:

2. How can I query all of "Log" records in a single "Site" for an average
"ResponseTime"?

------------------------------

<?xml version="1.0" standalone="yes" ?>
<Sites>
<Site Host="www.mysite1.com" IP="1.1.1.1" />
<Site Host="www.mysite2.com" IP="1.1.1.2" />
<Site Host="www.mysite3.com" IP="1.1.1.3">
<Log Time="1/1/2008 12:00:00 AM" Status="Success" ResponseTime="10" />
<Log Time="1/1/2008 12:00:01 AM" Status="Failure" ResponseTime="10" />
</Site>
<Site Host="www.mysite4.com" IP="1.1.1.4">
<Log Time="1/1/2008 12:00:00 AM" Status="Success" ResponseTime="10" />
<Log Time="1/1/2008 12:00:01 AM" Status="Failure" ResponseTime="10" />
</Site>
</Sites>

Here is an example that computes the average ResponseTime for those Site
elements that have at least on Log child element with a ResponseTime
attribute:

Imports System
Imports System.Xml.XPath
Module Module1

Sub Main()
Dim doc As New XPathDocument("..\..\XMLFile1.xml")
For Each site As XPathNavigator In
doc.CreateNavigator().Select("Sites/Site[Log/@ResponseTime]")
ComputeAverage(site)
Next
End Sub

Sub ComputeAverage(ByVal site As XPathNavigator)
Console.WriteLine(site.Evaluate("sum(Log/@ResponseTime) div
count(Log/@ResponseTime)"))
End Sub

End Module
So with XPath the solution is to evaluate the XPath expression
sum(Log/@ResponseTime) div count(Log/@ResponseTime)
with the Site element as the context node.

--

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/

[=?Utf-8?B?SmFzb25UODA=?=]

That worked. THANKS!

--
Jasont80
"Martin Honnen" wrote:

JasonT80 wrote:

2. How can I query all of "Log" records in a single "Site" for an average
"ResponseTime"?

------------------------------

<?xml version="1.0" standalone="yes" ?>
<Sites>
<Site Host="www.mysite1.com" IP="1.1.1.1" />
<Site Host="www.mysite2.com" IP="1.1.1.2" />
<Site Host="www.mysite3.com" IP="1.1.1.3">
<Log Time="1/1/2008 12:00:00 AM" Status="Success" ResponseTime="10" />
<Log Time="1/1/2008 12:00:01 AM" Status="Failure" ResponseTime="10" />
</Site>
<Site Host="www.mysite4.com" IP="1.1.1.4">
<Log Time="1/1/2008 12:00:00 AM" Status="Success" ResponseTime="10" />
<Log Time="1/1/2008 12:00:01 AM" Status="Failure" ResponseTime="10" />
</Site>
</Sites>

Here is an example that computes the average ResponseTime for those Site
elements that have at least on Log child element with a ResponseTime
attribute:

Imports System
Imports System.Xml.XPath
Module Module1

Sub Main()
Dim doc As New XPathDocument("..\..\XMLFile1.xml")
For Each site As XPathNavigator In
doc.CreateNavigator().Select("Sites/Site[Log/@ResponseTime]")
ComputeAverage(site)
Next
End Sub

Sub ComputeAverage(ByVal site As XPathNavigator)
Console.WriteLine(site.Evaluate("sum(Log/@ResponseTime) div
count(Log/@ResponseTime)"))
End Sub

End Module
So with XPath the solution is to evaluate the XPath expression
sum(Log/@ResponseTime) div count(Log/@ResponseTime)
with the Site element as the context node.

--

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/