Entity Framework 4 – The selected stored procedure returns no columns (part 2)

My original post on this topic, Entity Framework 4 – The selected stored procedure returns no columns, has been getting quite a lot of hits recently and I realize that of all the solutions I gave on that page the one I use the most is the one that’s mentioned way down the page in a comment.  So I thought it would be a good idea to highlight it.

The simplest solution to this issue is based on some data given by Frank Lan, a guy from MS Online Community Support on the SilverLight forums.  He said:

I did some research on how Visual Studio gets the column information. If you open SQL Server profiler when you click “Get Column Information”, you will find that Visual Studio queries against database to get the column information. One query I notice is that Visual Studio tries to execute the store procedure with all parameters set to be null. I am not sure if this is the way Visual Studio determines whether there’s column information or not. But I suggest you trying to execute your query in this way to see if there’s any column returned by your store procedure. Of course you can monitor the profiler your own to find more useful information.

That suggested a simple way to handle any situation where you have applied the solutions I gave in the original article (don’t just ignore those solutions and do this easy one) or where you are forced to use temp tables because temp variables won’t do and you still can’t get the columns:

Stick an “if” statement at the top of your sproc that checks if all parameters are null and if true returns the structure.

For Example:
if @param1 is null and @param2 is null then
begin
select
cast(null as varchar(10)) as Column1,
cast(null as bit) as Column2,
cast(null as decimal) as Column3
end

Just be aware that the casts are required otherwise EF won’t be able to tell what the data types are supposed to be.  Even if you return values instead of nulls you still need the casts.

Hope that helps.

Podcast Introductions to node.js

I’ve recently come across some good intro podcasts on node.js.

I’ve been listening to the .NET Rocks podcast for a while now and their latest show is a talk with Tomasz Janczuk, the guy at Microsoft who is working on porting node.js to Windows and IIS. It’s a good intro for all types of developers but is probably aimed at .NET devs more than open source or Java devs.

» .NET Rocks – Show 711: Tomasz Janczuk Builds Web Apps with node.js – As well as the basics on what node.js is and how you use it, there is some very good data on when you’d use iisnode versus basic node.exe.

I only came across the Herding Code podcast a few weeks ago, but I like it so much that I’ve already caught up on all the shows for this year and a couple of the earlier ones that covered topics I’m interested in. The four presenters are real pro devs and the discussions are always really lively, funny and interesting.

There are two node.js related shows:

» Herding Code 102: Tim Caswell on Node.js – this is an excellent intro that goes beyond the basics and explains the event loop of node and the non-blocking async programming model it uses. This gives you a good foundation.

» Herding Code 122: Bert Belder on porting Node.js to Windows – This is about more than just porting node to Windows, which is very interesting in itself, it builds on show 102, so listen to that one first.

I hope these are helpful.