OdataModelConventionBuilder does not understand DbContext generated model

Question

I am currently working with WebApi OData on a project and have run into a very frustrating problem. I am using an Entity Framework database-fist model using the EF5 DbContext setup as is the default with Visual Studio 2012 and .NET 4.5. My problem is that if I use the OdataModelConventionBuilder on my entities from Entity Framework to generate my Edm for the OData endpoints, the OData $metadata does not find any of the Key values nor does it properly generate the associations between entities.

I believe that this is because the DbContext generated entities do not have the DataAnnotation attributes on them. If I add the attributes, the keys suddenly work, but this is not a solution since those attributes will be lost if the model is ever regenerated.

Is there a known workaround for this issue?

I am currently having to build my OData Edm by hand using the ODataModelBuilder and it is proving tedious and error-prone.

RaghuRam Nadiminti RaghuRam Nadiminti · Accepted Answer · 2013-04-04T16:12:52

You can use the ODataConventionModelBuilder in a partial fashion i.e give it the information that you would have given through the attributes. Assuming you have a 'Customer' type with key property being 'Name' and a 'Customers' entityset, instead of doing something like,

ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
var customers = builder.Entityset<Customer>("Customers");
return builder.GetEdmModel();

you can do something like,

ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
var customers = builder.Entityset<Customer>("Customers");
customers.EntityType.HasKey(c => c.Name); // tell the key explicitly through code
return builder.GetEdmModel();

That should infer the rest of the model.

Also, we have this bug tracking to re-use the EDM model created by Entityframework or some other library. We have it scheduled for the current release. Hopefully, your scenario would be simpler then.

OdataModelConventionBuilder does not understand DbContext generated model

1 Answers