Working on a project which uses ADO.NET data services for a small part of it. I put the ADO.NET Data Services portion together (add the files, put the EF data model together, link it up etc…) on my machine (Windows 2008 Server, SQL 2008, VS 2008) and it all worked great! Checked into source control and then went about doing something else, ignorant of the coming problem.
Then the developer who would actually consume it (we are consuming it in C# using LINQ) came to me saying that nothing worked :( All we get is the generic ADO.NET Data Services error: “An error occurred while processing this request”. We removed the where clauses and everything worked perfectly, which hinted to me the LINQ/EF expression tree was borking out somewhere. So we went to the EF data model, told it to update and it did a change under the surface and everything worked again?!
I love TFS because it allowed me to compare my version and the updated one easily and their was one tiny change (literally 1 byte!) in the edmx file (not the .cs backing file, the edmx file itself). Turns out that in dev they are using SQL Server 2005 and I built the model with SQL Server 2008 - now note there is ZERO 2008 special features in use, but it seems that the EF expression tree doesn’t care and try’s to use some SQL 2008 magic cause it thinks it is SQL 2008. This is controlled by the ProviderManifestToken attribute! Changing that to 2005 (which is what the update did automatically for me) solved the problem!
