Entity Framework Bulk Update

We often need to update items in bulk while working with Entity Framework. As good as it is, entity framework has its quirks like any other ORM tools. Entity Framework bulk update is needed only when you need to update multiple items at a go.

We used classic ADO.NET stored procedure for our long-running processes. But when updating multiple items from models at once we found it rather a tedious process to maintain. We were already using the entity framework in our project for data access along with the classic ADO.NET. So decided to use entity framework for bulk update operations.

In this very short article, I am showing a way how we have updated our list of objects using entity framework DB first. Here we want to update some particular property of a list into our database.

ItemObject = Object model from database
list = the list of items we want to update
ContextFactory.GetContext() = A factory method to get a particular context. This is our application specific method.

Here we updated just a few properties in our model. If we want entity framework to update the whole model we need to set the entity state property to modified for the whole entity.

After the loop is finished, save the context. The data will be updated in the database.

Entity framework bulk update or insert operation is slow. I’d recommend any other option if we can find to do such bulk updates. But in terms of code maintenance, we found it feasible in our case. Be sure to use it when you need this kind of operation.

I hope this helps you guys. If you have any suggestion regarding anything or how should I improve please don’t forget to knock. I’d really appreciate your feedback.

Unable to load the specified metadata resource – Entity Framework

We got this issue when we were calling the EDMX file from our DataAccess project. We used entity framework database first approach.

Our EDMX file lied in another project and the DataAccess project was used to do various operations on the EDMX file. But we forgot to add the connection string to the corresponding EDMX file into our DataAccess Project. Hence, this very ambiguous message :

[code language=”csharp”]"Unable to load the specified metadata resource" [/code]

The reason is Res://*/ is a URI which points to resources in the CURRENT assembly. If the Edm is defined in a different assembly from the code which is using it, res://*/ is not going to work because the resource cannot be found. So we need to add the connection string to all the projects that it’s being used in.
So I decided to dig a bit more and found out some possible reasons for this exception in entity framework including ours:

  • The EDMX resides in a separate project. We have to maintain connection string in both the projects. (This is our problem)
  • The MetadataArtifactProcessing property of the model You may have been changed to Copy to Output Directory.
  • There might be a post-compile task to embed the EDMX in the assembly and it’s giving errors for some reason.
  • The connection string itself is wrong. Yes I know it’s a very small thing, but it happens a lot.

 

The mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type

This error occurred in our application with a particular case when we stored two procedures with the same name in two different databases. These databases were internally related. We used Entity Framework database first approach for our application.

As EF uses only class names to identify the type mapped in EDMX (namespaces are ignored) Рit is a convention to allow mapping classes from different namespaces to a single model, the EDMX could not differentiate the two classes generated from the stored procedures. So it threw this particular error-

[code language=”xml”]
The mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type
[/code]

So the solution is:

  • Don’t use classes with the same unqualified name.
  • Name your stored procedures differently even if they’re in separate databases if you’re planning to use them in a single BLL.