S#harp architecture mapping many to many and ado.net data services: A single resource was expected f
- by Leg10n
Hi, I'm developing an application that reads data from a SQL server database (migrated from a legacy DB) with nHibernate and s#arp architecture through ADO.NET Data services. I'm trying to map a many-to-many relationship. I have a Error class:
public class Error
{
public virtual int ERROR_ID { get; set; }
public virtual string ERROR_CODE { get; set; }
public virtual string DESCRIPTION { get; set; }
public virtual IList<ErrorGroup> GROUPS { get; protected set; }
}
And then I have the error group class:
public class ErrorGroup
{
public virtual int ERROR_GROUP_ID {get; set;}
public virtual string ERROR_GROUP_NAME { get; set; }
public virtual string DESCRIPTION { get; set; }
public virtual IList<Error> ERRORS { get; protected set; }
}
And the overrides:
public class ErrorGroupOverride : IAutoMappingOverride<ErrorGroup>
{
public void Override(AutoMapping<ErrorGroup> mapping)
{
mapping.Table("ERROR_GROUP");
mapping.Id(x => x.ERROR_GROUP_ID, "ERROR_GROUP_ID");
mapping.IgnoreProperty(x => x.Id);
mapping.HasManyToMany<Error>(x => x.Error)
.Table("ERROR_GROUP_LINK")
.ParentKeyColumn("ERROR_GROUP_ID")
.ChildKeyColumn("ERROR_ID").Inverse().AsBag();
}
}
public class ErrorOverride : IAutoMappingOverride<Error>
{
public void Override(AutoMapping<Error> mapping)
{
mapping.Table("ERROR");
mapping.Id(x => x.ERROR_ID, "ERROR_ID");
mapping.IgnoreProperty(x => x.Id);
mapping.HasManyToMany<ErrorGroup>(x => x.GROUPS)
.Table("ERROR_GROUP_LINK")
.ParentKeyColumn("ERROR_ID")
.ChildKeyColumn("ERROR_GROUP_ID").AsBag();
}
}
When I view the Data service in the browser like: http://localhost:1905/DataService.svc/Errors it shows the list of errors with no problems, and using it like http://localhost:1905/DataService.svc/Errors(123) works too.
The Problem
When I want to see the Errors in a group or the groups form an error, like: "http://localhost:1905/DataService.svc/Errors(123)?$expand=GROUPS" I get the XML Document, but the browser says:
The XML page cannot be displayed
Cannot view XML input using XSL style sheet. Please correct the error and then click the Refresh button, or try again later.
--------------------------------------------------------------------------------
Only one top level element is allowed in an XML document. Error processing resource 'http://localhost:1905/DataServic...
<error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
-^
I view the sourcecode, and I get the data. However it comes with an exception:
<error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
<code></code>
<message xml:lang="en-US">An error occurred while processing this request.</message>
<innererror xmlns="xmlns">
<message>A single resource was expected for the result, but multiple resources were found.</message>
<type>System.InvalidOperationException</type>
<stacktrace> at System.Data.Services.Serializers.Serializer.WriteRequest(IEnumerator queryResults, Boolean hasMoved)
at System.Data.Services.ResponseBodyWriter.Write(Stream stream)</stacktrace>
</innererror>
</error>
A I missing something??? Where does this error come from?
