TFS client object model provides a nice hierarchy of objects to use to our advantage. For example, you can navigate from the server scope to the project scope and then to the work items scope. And at any level you can enumerate the resources. This provides a convenient mechanism for the length and breadth of the organization.
The client object model is not the only thing. There's the server object model to be used at the server side. and the build process object model at the build machine.
The OData on the other hand gives the same flexibility outside the programming context. It is accessible over the web.
The way to navigate the OData from TFS is to use the OData model to find the workItem we are interested in. Here's how it would look like :
var proxy = CreateTFSServiceProxy(out baseURL, out teamProject, out workitemtype);
var workItems = proxy.Execute<WorkItem>(new Uri(string.Format(cultureInfo.InvariantCulture,
                                                             {0}/Projects('{1}')/WorkItems?$filter=Type eq '{2}' and Title eq '{3}' & $orderby=Id desc",
                                                             baseURL,
                                                             teamProject,
                                                             WorkItemType,
                                                             WorkItemTitle)))
                  .First();
 This lets us specify the filter in the Uri to get the results to we want. Then it can be processed or reported in any way.
or another way to execute the queries could be as follows:
var queryProxy = new TFSQueryProxy(Uri, ICredentials)
var queries = queryProxy.GetQueriesByProjectKey