Interstage Shunsaku Data Manager Application Development Guide - Microsoft(R) Windows(R) 2000/ Microsoft(R) Windows Server(TM) 2003 - - UNIX -

H.1.5 Aggregating the Values of XML Documents that Match Search Conditions

When performing a search, the user sometimes prefers to obtain the search results after the value of a specific element has been aggregated.

To show how the VB .NET are used, the following example specifies the location in the search conditional expression and extracts the cheapest accommodation rate, the most expensive accommodation rate, and the average accommodation rate.

Search Conditions

'Among the hotels with a vacancy on 2006/07/18, I want to use aggregation to obtain the cheapest hotel, the most expensive hotel and the average hotel rate according to district.'

Specify the date (2006/07/18) as the search condition and then apply aggregation expressions (min, max and avg) to the results to obtain aggregated results.

An Example of Using the APIs

The following is a sample program using the VB .NET.

Imports System
Imports Fujitsu.Shunsaku
Imports System.ComponentModel

Class SampleSort2

  Shared Public Function Main( ByVal args() As String ) As Integer
    Dim service As ShunService = Nothing

    Try
      '' Create ShunService
      service = new ShunService()

      '' Connect Shunsaku by specifying the host name and port number
      service.Host = "DirSrv1"
      service.Port = 33101
      service.Connect()

      '' Create ShunSearchRequirement
      Dim req As ShunSearchRequirement = new ShunSearchRequirement()
      
      '' Set each type of search conditions
      req.QueryExpression = "/document/information/date == '2006/07/18'"
      req.ReturnExpression = "/document/base/city/text(), min(/document/base/price/text()), max(/document/base/price/text()), avg(/document/base/price/text())"
      req.SortExpression = "/document/base/city/text()"
      req.ReplyNumber = 1
      req.RequestCount = 30
      
      '' Specify the search condition and execute the search
      Dim rs As ShunResultSet = service.Search( req )

      '' Display the search results
      '' Obtain the data that corresponds to the search conditions
      Dim i As Integer = 0
      For Each record As ShunRecord In rs.Records
        i += 1
        Console.WriteLine( "[Result] Item No. {0}:", i )
        Dim result As String()() = record.GetDividedData()
        Console.WriteLine("  District          :{0}", result( 0 )( 0 ) )
        Console.WriteLine("  Cheapest rate:{0}", result( 1 )( 0 ) )
        Console.WriteLine("  Most expensive rate:{0}", result( 2 )( 0 ) )
        Console.WriteLine("  Average rate:{0}", result( 3 )( 0 ) )
      Next

      '' Close the connection to Shunsaku
      service.Disconnect()
    
    Catch e As ShunContinuousException
      '' Processing to perform if ShunContinuousException occurs
      Try
        If Not service Is Nothing And service.State = ShunConnectionState.Open Then

          service.Disconnect()
        End If
      Catch ex As ShunException
        Console.WriteLine( "Error message : {0}", ex.Message )
      End Try
      Console.WriteLine( "Error message : {0}", e.Message )
    
    Catch e As ShunConnectionTerminatedException
      '' Processing to perform if ShunConnectionTerminatedException occurs
      Console.WriteLine( "Error message : {0}", e.Message )

    End Try
  End Function
End Class

Execution Results

[Result] Item No.1:
  District: Adelaide
  Cheapest rate: 100
  Most expensive rate: 300
  Average rate: 200
[Result] 2nd:
  District: Sydney
  Cheapest rate: 150
  Most expensive rate: 350
  Average rate: 250