An example of the .NET web service accessing an SDE could look something like this
[WebMethod(Description = "Returns Flow Control History Details")]
public DataTable FlowControlHistory(String objectID)
{
DataTable FlowTable = new DataTable();
System.Data.OleDb.OleDbConnection connection = new System.Data.OleDb.OleDbConnection("<your connection string here>");
connection.Open();
// build a sql expression to access your database data
// using a passed OBJECTID from a feature in flex
string strSQL = "SELECT DISTINCT t1.FLOWID " +
"FROM sde.SSCOMPLEXFLOWCONTROLHISTORY as t1 " +
"WHERE t1.OBJECTID = '" + objectID + "' " +
"UNION " +
"SELECT DISTINCT t2.FLOWID " +
"FROM sde.SSFLOWCONTROLHISTORY as t2 " +
"WHERE t2.OBJECTID = '" + objectID + "' " +
"ORDER BY FLOWID;
System.Data.OleDb.OleDbDataAdapter Adapter = new System.Data.OleDb.OleDbDataAdapter(strSQL, connection);
Adapter.Fill(FlowTable);
try
{
FlowTable.TableName = "Table";
}
finally
{
connection.Close();
}
return FlowTable;
}
Then in Flex, you'd do something like this.
protected var service:WebService;
protected var retry:uint = 0;
// send your Web Service WSDL to define a web service
public function setWsdl(value:String):void {
service = new WebService();
service.showBusyCursor = true;
service.wsdl = value;
service.addEventListener(FaultEvent.FAULT, WsdlFault, false, 0, true);
service.loadWSDL();
}
protected function onWsdlFault(fault:FaultEvent, token:Object = null):void {
// I always try to load a web service twice if I get a load error.
// Just in case, my network can laugh at me sometimes
retry++;
if (retry < 2)
service.loadWSDL();
else {
service.removeEventListener(FaultEvent.FAULT, WsdlFault);
Alert.show("A Web Service has failed to load. Please close the application and try again.", "Error");
}
}
// function that will call my web service
public function findRelatedFlowData(objectID:String):void {
var responder:AsyncResponder = new AsyncResponder(onFlowDataResults, onFault);
var request:AsyncToken = service.FlowControlHistory(objectID);
request.addResponder(responder);
}
proteced function onFlowDataResults(result:ResultEvent, token:Object = null):void {
var ac:ArrayCollection = result.result.Tables.Table.Rows;
// do something with results here
}
protected function onFault(fault:FaultEvent, token:Object = null):void {
// I always try to load a web service twice.
Alert.show("A Web Service error has occurred.", "Error");
}
This has always worked for me, plus by using C# or VB.NET you get a bit more control over your query. The relates in the ESRI API are still great and I use them for large data dumps, but I still have a lot of these unique queries of my SDE.
