Web Api Returning Json - [System.NotSupportedException] Specified method is not supported. (Sybase Ase)

Question

I'm using Web api with Entity Framework 4.2 and the Sybase Ase connector.

This was working without issues returning JSon, until I tried to add a new table.

  return db.car
             .Include("tires")
             .Include("tires.hub_caps")
             .Include("tires.hub_caps.colors")
             .Include("tires.hub_caps.sizes")
             .Include("tires.hub_caps.sizes.units")
             .Where(c => c.tires == 13);

The above works without issues if the following line is removed:

.Include("tires.hub_caps.colors")

However, when that line is included, I am given the error:

""An error occurred while preparing the command definition. See the inner exception for details."

The inner exception reads: "InnerException = {"Specified method is not supported."}" "source = Sybase.AdoNet4.AseClient"

The following also results in an error:

  List<car> cars = db.car.AsNoTracking()
             .Include("tires")
             .Include("tires.hub_caps")
             .Include("tires.hub_caps.colors")
             .Include("tires.hub_caps.sizes")
             .Include("tires.hub_caps.sizes.units")
             .Where(c => c.tires == 13).ToList();

The error is as follows:

An exception of type 'System.Data.EntityCommandCompilationException' occurred in System.Data.Entity.dll but was not handled in user code

Additional information: An error occurred while preparing the command definition. See the inner exception for details.

Inner exception: "Specified method is not supported."

This points to a fault with with the Sybase Ase Data Connector.

I am using data annotations on all tables to control which fields are returned. On the colors table, I have tried the following annotations to limit the properties returned just the key:

[JsonIgnore]
 [IgnoreDataMember]

Any ideas what might be causing this issue?

Alternatively, if I keep colors in and remove,

 .Include("tires.hub_caps.sizes")
 .Include("tires.hub_caps.sizes.units")

then this works also. It seems that the Sybase Ase connector does not support cases when an include statement forks from one object in two directions. Is there a way round this? The same issue occurs with Sybase Ase and the progress data connector.

The issue does not occur in a standard ASP.net MVC controller class - the problem is with serializing two one to many relationships on a single table to JSON.

This issue still occurs if lazy loading is turned on.

It seems to me that this is a bug with Sybase ASE, that none of the connectors are able to solve.