Data deletion through WFC data service client applciation - oracle

Question

I am self hosting a Odata WCF data service in a console application that is hooked up to an Oracle database through ADO.Net entity model. i am using Microsoft.Data.Services v5.5.0.I can read/write data through the client application but cannot delete. Here is the code:
Server code:
public class tos_host : DataService<Entities>
{
public static void InitializeService(DataServiceConfiguration config)
{
// TODO: set rules to indicate which entity sets and service operations are visible, updatable, etc.
// Examples:
config.SetEntitySetAccessRule("*", EntitySetRights.All);
config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;
}
}
class Program
{
static void Main(string[] args)
{
Uri[] baseAddresses = new Uri[1];
baseAddresses[0] = new Uri("http://localhost:4444/tos_host");
using (DataServiceHost host = new DataServiceHost(typeof(tos_host), baseAddresses))
{
host.Open();
Console.WriteLine("TOS host up and running.....");
Console.ReadLine();
host.Close();
}
}
}
Client code:
static void Main(string[] args)
{
Entities context = new Entities(new Uri("http://localhost:4444/tos_host"));
context.MergeOption = MergeOption.OverwriteChanges;
context.IgnoreMissingProperties = true;
var container = new CONTAINERS();
container.CONTAINER_ID = "CONT";
container.TIMESTAMP=DateTime.UtcNow;
context.AddToCONTAINERS(container);
context.SaveChanges();
CONTAINERS container_2 = context.CONTAINERS.Where(c => c.CONTAINER_ID == "CONT").First();
context.DeleteObject(container_2);
context.SaveChanges(); //Here i get an exception
}
The exception is as follows:
System.Data.Services.Client.DataServiceRequestException was unhandled
HResult=-2146233079
Message=An error occurred while processing this request.
Source=Microsoft.Data.Services.Client
StackTrace:
at System.Data.Services.Client.SaveResult.HandleResponse()
at System.Data.Services.Client.BaseSaveResult.EndRequest()
at System.Data.Services.Client.DataServiceContext.SaveChanges(SaveChangesOptions options)
at System.Data.Services.Client.DataServiceContext.SaveChanges()
at client_test_lnew_libs.Program.Main(String[] args) in c:\Users\ITS\Desktop\rmcs_tests \client_test_lnew_libs\client_test_lnew_libs\Program.cs:line 27
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException: System.Data.Services.Client.DataServiceClientException
HResult=-2146233079
Message=<?xml version="1.0" encoding="utf-8"?><m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"><m:code /><m:message xml:lang="el-GR">Resource not found for the segment 'CONTAINERS'.</m:message></m:error>
StatusCode=404
InnerException:
What am i doing wrong? Any clues?

Answer 1

From my understanding, when you query and no results are returned, the dataservice will throw the exception you're seeing. To return an empty set instead, you need to set the IgnoreResourceNotFoundException property:
context.IgnoreResourceNotFoundException = true;
See the following blog post for more information:
http://blogs.msdn.com/b/peter_qian/archive/2009/03/20/safe-resource-not-found-404-exception-handling-in-ado-net-data-service-client.aspx?Redirected=true