Reading Time: 2 minutes. 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, your application is probably built on .NET Framework and Entity Framework. Let’s get into it! Error When debugging/running your code you get an error like this: An exception of type ‘System.InvalidOperationException’ occurred in EntityFramework.dll but was not handled in […]
Tag: EF6
Applying Entity Framework’s Code-First Migrations against a Database in Azure by running Update-Database
Reading Time: 3 minutes. 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 […]
Exception of type ‘System.OutOfMemoryException’ was thrown.
Reading Time: 3 minutes. This post describes one of the more no-brainerish ways of fixing a ‘System.OutOfMemoryException’ exceptions being thrown in your ASP.Net MVC application using C# and Entity Framework. Problem While developing a web project, for example an ASP.NET MVC web application which is using EF, sometimes when handling a lot of data or complex entities on your dev machine, you encounter this error: OutOfMemoryException: Exception of type ‘System.OutOfMemoryException’ was thrown.] System.Text.StringBuilder.ToString() +35 System.IO.StreamReader.ReadToEnd() +123 System.Web.Optimization.BundleFile.ApplyTransforms() +74 System.Web.Optimization.DefaultBundleBuilder.BuildBundleContent(Bundle bundle, BundleContext context, IEnumerable`1 files) +472 System.Web.Optimization.Bundle.GenerateBundleResponse(BundleContext context) +127 System.Web.Optimization.Bundle.GetBundleResponse(BundleContext […]
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.”
Reading Time: 2 minutes. While using Entity Framework and code-first migrations, Entity Framework (EF) creates the indexes for you – but what if you need to create a custom one, explicitly based on certain field / column? Then you’ll have to tell EF which one to use as a key column. Usually, it’s easy – you just add the following annotation to the columns you’ll be using: [Index(“OfficialIds”, 1)] public int AreaId { get; set; } [Index(“OfficialIds”, 2)] public string EstateId { get; set; } (example stripped of extra code and other columns for clarity) And after adding the migration (Add-Migration… commandlet) you get […]
Fixing “An error occurred while updating the entries” while running code-first migrations in MVC 5 app
Reading Time: 5 minutes. This post describes an issue with EF’s code-first migrations, when mapping between DB’s DateTime (datetime2) and C#’s DateTime kind of fails, and results in Update-Database cmdlet failing. It’s more or less a prime example of a situation, where the error itself tells very little about the actual issue, and since debugging code-first migrations is kind of difficult (see the best tips for that here!), it’s cumbersome to investigate. Symptoms An exception of type ‘System.Data.Entity.Infrastructure.DbUpdateException’ occurred in EntityFramework.dll but was not handled in user code. I’ve […]