Fixing error “No Entity Framework provider found for the ADO.NET provider with invariant name ‘System.Data.SqlClient'”

No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient'

This post describes the fix to error “No Entity Framework provider found for the ADO.NET provider with invariant name ‘System.Data.SqlClient'”, which Visual Studio throws at your face when you try to run an application on any Windows-based system (or which you’ve dug out of event logs). Also, you’re probably using Entity Framework in your project.

Error

When debugging/running your code you get an error like this:

The running of the program is stopped there, and removing and readding the nuget packages and/or other references to dlls does not help. I tried also making all kinds of changes to my web.config, but nothing seemed to help. There’s a simple fix available, though!

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Applying Entity Framework’s Code-First Migrations against a Database in Azure by running Update-Database

This post describes how to run Entity Framework’s code-first migrations against a database located in the Windows Azure. This is done by running Update-Database commandlet with suitable switches, see below.

The problem and symptoms

Okay, so you’re developing your MVC+EF cool web app with a database in Azure, and you’re using code-first migrations. Cool! What’s nice with code-first-migrations is the fact they are run automatically even in the cloud the next time your app is running (as long as you publish your app with that little box ticked – something like in the screen capture below). But wait – what if there are conflicts – what kind of errors are you going to get?

 

Azure Web Publish

Azure Web Publish

Not very useful ones, I’m afraid, and it’s a pain navigating the Azure portal to fetch the log files. At some point – for me, it wasn’t the first time I ran the web app, but the phase when I was logging in – you’ll be getting the error the migrator internally throws. That might be enough to point you to the right direction, and maybe you’ll be able to figure out what’s wrong! But if that’s not the case, here’s the way to run Update-Database against your Azure Database!

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Exception of type ‘System.OutOfMemoryException’ was thrown.

IIS8

This post describes one of the more no-brainerish ways of fixing a ‘System.OutOfMemoryException’ exceptions being thrown in your MVC ASP.Net application using Entity Framework.

Problem

While developing a web project, for example ASP.NET MVC with EF, sometimes when handling a lot of data or complex entities on your dev machine, you encounter this error:

Reason

By default, Visual Studio uses 32-bit version of IIS Express for your deployments. In case you know what you’re doing, it’s safe and easy to change this, though.

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Fixing the error: “Column XX in table dbo.YY is of a type that is invalid for use as a key column in an index.”

entity-framework-logo

While using Entity Framework and code-first migrations, EF creates the indexes for you – but what if you need to create a custom one? Usually, it’s easy – you just add the following annotation to the columns you’ll be using:

(example stripped of extra code and other columns for clarity)

And after adding the migration (Add-Migration…) you get something like this:

But what if, when running Update-Database, you get an error like:

There’s a quick and simple solution.

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Fixing “An error occurred while updating the entries” while running code-first migrations in MVC 5 app

Update-Database error

This post describes an issue with EF’s code-first migrations, when mapping between DB’s DateTime and C#’s DateTime kind of fails, and results in Update-Database cmdlet failing.

Symptoms

While running Update-Database in a code-first ASP.NET MVC5 + EF6 -project, you get a following (or similar) error:

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