Entity Framework 6 SQL Server provider based on Microsoft.Data.SqlClient

This Entity Framework 6 provider is a replacement provider for the built-in SQL Server provider.

This provider depends on the modern Microsoft.Data.SqlClient ADO.NET provider, which includes the following advantages over the currently used driver:

• Current client receiving full support in contrast to System.Data.SqlClient, which is in maintenance mode
• Supports new SQL Server features, including support for the SQL Server 2022 enhanced client protocol (TDS8)
• Supports most Azure Active Directory authentication methods
• Supports Always Encrypted with .NET

Notice that this provider is a runtime only update and will not work with the existing Visual Studio tooling.

The latest build of this package is available from NuGet

Configuration

There are various ways to configure Entity Framework to use this provider.

You can register the provider in code using an attribute:

[DbConfigurationType(typeof(MicrosoftSqlDbConfiguration))]
public class SchoolContext : DbContext
{
    public SchoolContext() : base()
    {
    }

    public DbSet<Student> Students { get; set; }
}

If you have multiple classes inheriting from DbContext in your solution, add the DbConfigurationType attribute to all of them.

Or you can use the SetConfiguration method before any data access calls:

 DbConfiguration.SetConfiguration(new MicrosoftSqlDbConfiguration());

Or add the following lines to your existing derived DbConfiguration class:

SetProviderFactory(MicrosoftSqlProviderServices.ProviderInvariantName, Microsoft.Data.SqlClient.SqlClientFactory.Instance);
SetProviderServices(MicrosoftSqlProviderServices.ProviderInvariantName, MicrosoftSqlProviderServices.Instance);
// Optional
SetExecutionStrategy(MicrosoftSqlProviderServices.ProviderInvariantName, () => new MicrosoftSqlAzureExecutionStrategy());

You can also use App.Config based configuration:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
        <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />    
    </configSections>
    <entityFramework>
        <providers>
            <provider invariantName="Microsoft.Data.SqlClient" type="System.Data.Entity.SqlServer.MicrosoftSqlProviderServices, Microsoft.EntityFramework.SqlServer" />
        </providers>
    </entityFramework>
    <system.data>
        <DbProviderFactories>
           <add name="SqlClient Data Provider"
             invariant="Microsoft.Data.SqlClient"
             description=".NET Framework Data Provider for SqlServer"
             type="Microsoft.Data.SqlClient.SqlClientFactory, Microsoft.Data.SqlClient" />
        </DbProviderFactories>
    </system.data>
</configuration>

If you use App.Config with a .NET 6 or later app, you must remove the <system.data> section above and register the DbProviderFactory in code once:

DbProviderFactories.RegisterFactory(MicrosoftSqlProviderServices.ProviderInvariantName, Microsoft.Data.SqlClient.SqlClientFactory.Instance);

EDMX usage

If you use an EDMX file, update the Provider name:

<edmx:Edmx Version="3.0" xmlns:edmx="http://schemas.microsoft.com/ado/2009/11/edmx">
  <edmx:Runtime>
    <edmx:StorageModels>
      <Schema Namespace="ChinookModel.Store" Provider="Microsoft.Data.SqlClient" >

In order to use the EDMX file with the Visual Studio designer, you must switch the provider name back to System.Data.SqlClient

Also update the provider name inside the EntityConnection connection string - provider=Microsoft.Data.SqlClient

 <add 
    name="Database" 
    connectionString="metadata=res://*/EFModels.csdl|res://*/EFModels.ssdl|res://*/EFModels.msl;provider=Microsoft.Data.SqlClient;provider connection string=&quot;data source=server;initial catalog=mydb;integrated security=True;persist security info=True;" 
    providerName="System.Data.EntityClient" 
 />

Code changes

To use the provider in an existing solution, a few code changes are required (as needed).

using System.Data.SqlClient; => using Microsoft.Data.SqlClient;

using Microsoft.SqlServer.Server; => using Microsoft.Data.SqlClient.Server;

The following classes have been renamed to avoid conflicts with classes that uses System.Data.SqlClient in the existing SQL Server provider:

SqlAzureExecutionStrategy => MicrosoftSqlAzureExecutionStrategy

SqlDbConfiguration => MicrosoftSqlDbConfiguration

SqlProviderServices => MicrosoftSqlProviderServices

SqlServerMigrationSqlGenerator => MicrosoftSqlServerMigrationSqlGenerator

SqlSpatialServices => MicrosoftSqlSpatialServices

SqlConnectionFactory => MicrosoftSqlConnectionFactory

LocalDbConnectionFactory => MicrosoftLocalDbConnectionFactory

Known issues

Azure App Service with .NET Framework and connection strings configuration

If you use Azure App Service with .NET Framework and the connection strings configuration feature, you can encounter runtime issues, as the ProviderName connection string setting in this scenario is hardcoded to System.Data.SqlClient.

Solution is to use a derived MicrosoftSqlDbConfiguration class like this:

public class AppServiceConfiguration : MicrosoftSqlDbConfiguration
{
    public AppServiceConfiguration()
    {
        SetProviderFactory("System.Data.SqlClient", Microsoft.Data.SqlClient.SqlClientFactory.Instance);
        SetProviderServices("System.Data.SqlClient", MicrosoftSqlProviderServices.Instance);
        SetExecutionStrategy("System.Data.SqlClient", () => new MicrosoftSqlAzureExecutionStrategy());
    }
}

Then use this derived class in the code-based configuration described above.

EntityFramework.dll installed in GAC

If an older version of EntityFramework.dll is installed in the .NET Framework GAC (Global Assembly Cache), you might get this error:

The 'PrimitiveTypeKind' attribute is invalid - The value 'HierarchyId' is invalid according to its datatype

Solution is to remove the .dll from the GAC. EF6 assemblies should never be installed in the GAC.