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

10.3.2.6 Obtaining Sorted Data

Sometimes it is useful to be able to sort the results of a search, using a particular element as a sort key.

To obtain sorted partial information about the data, use the SortExpression property of the ShunSearchRequirement object.

The following diagram shows the process for obtaining data after it has been sorted.

[Figure 10-10 Flow of the Process for Obtaining Data after It Has Been Sorted]

When search results are sorted, the sort process looks up all of the XML documents that match the search conditions. To improve response performance, it is important to narrow down the data to be sorted by specifying a search expression that produces an appropriate number of hits. Set the search conditions in the GetHitCount method to look for the number of XML documents that match the search conditions before the sort process.

Sample Code for C# .NET

ShunService service = new ShunService();
service.Connect();

ShunSearchRequirement req = new ShunSearchRequirement();                       (1)
req.QueryExpression = "/document/base/prefecture == 'Sydney'";                 (1)
req.ReturnExpression = "/document/base/name, /document/base/price";            (1)
req.SortExpression = "val(/document/base/price/text()) DESC";                  (1)

ShunResultSet rs = service.Search( req );                                      (2)
Console.WriteLine ( "[Number of hits] = {0}", rs.HitCount );
int i = 0;
foreach ( ShunRecord record in rs.Records ) {                                  (3)
  ++i;
  Console.WriteLine( "[Result]Item No.{0} = {1}", i, record.Data );            (3)
} 

service.Disconnect();

Sample Code for VB .NET

Dim service As New ShunService()
service.Connect()

Dim req As New ShunSearchRequirement()                                    (1)
req.QueryExpression = "/document/base/prefecture == 'Sydney'"             (1)
req.ReturnExpression = "/document/base/name, /document/base/price"        (1)
req.SortExpression = "val(/document/base/price/text()) DESC"              (1)

Dim rs As ShunResultSet =  service.Search( req )                          (2)
Console.WriteLine( "[Number of hits] = {0}", rs.HitCount )
Dim i As Integer =  0 
For Each record As ShunRecord In rs.Records                               (3)
  i += 1
  Console.WriteLine( "[Result] Item No.{0} = {1}", i, record.Data )       (3)
Next

service.Disconnect()

(1) Set the Seach Conditions

Create the ShunSearchRequirement object, and then set the following properties as the search conditions. If the sort process is used, set the sort expression at the SortExpression properties.

[Table 10-6 List of Properties]

Property	Description
QueryExpression	Specifies the search expression. This property cannot be omitted.
ReturnExpression	Specifies the return expression.
SortExpression	Specifies the sort expression. This property can be omitted if the sort process is not used.
ReplyNumber	Specifies the reply start number. 1 is specified if it is omitted.
RequestCount	Specifies the number of items to return per request. If it is omitted, the number of search results that can be returned will be the same as specifying at the AnsMax in the conductor environment file or the director environment file.

Refer to Appendix B Format of Search, Return and Sort Expressions for more information on search expressions and return expressions.

Refer to B.5 Sort Expressions for more information on sort expressions.

The total length of the sort keys specified in the sort expression determines the number of data items that can be returned. A maximum of 1,000 items can be returned. No more data can be returned even if a higher value is specified for the reply start number or the number of items to return per request. Use the ReturnableCount property to obtain the maximum number of data items that can be returned.

Appendix C Allowable Values provides a guide to the key lengths and the number of data items that can be returned.

Consecutive data can be extracted by specifying an acquisition start position. This can be used to extract upwards of 1,000 items of data. Refer to 10.3.2.7 Obtaining Consecutive Groups of XML Documents that Match Conditions for details.

(2) Execute the Search (Create a ShunResultSet Object)

For the search, specify and use the ShunSearchRequirement object that the search conditions have been set by the Search method. A ShunResultSet object will be created to hold the results of the search.

(3) Extract the Results of the Search

Extract 1 record of ShunRecord object from the ShunResultSet object. Then extract the XML documents from the ShunRecord object.

Different properties or methods can be used to extract XML documents for different objectives. The following table shows the properties or methods that can be used.

[Table 10-7 Properties and Methods that Can be Used to Extract XML Documents]

Property or method	Function
Data property	Extracts XML documents as String objects.
GetDividedData method	Extracts XML documents as a two-dimensional array of String objects.
GetStream method	Extracts XML documents as Stream objects.