Microsoft.Data.SqlClient namespace and compatibility

The Microsoft.Data.SqlClient namespace contains the supported .NET data provider for SQL Server-compatible databases. It began as a fork of System.Data.SqlClient and retains the familiar ADO.NET programming model while shipping new SQL Server features independently of the .NET runtime.

Use Microsoft.Data.SqlClient for new development.

Install and import the namespace

Add the NuGet package:

dotnet add package Microsoft.Data.SqlClient

Import the namespace:

using Microsoft.Data.SqlClient;

Most applications use SqlConnection, SqlCommand, SqlParameter, SqlDataReader, and SqlTransaction. For the complete public surface, see the Microsoft.Data.SqlClient API reference.

Relationship to ADO.NET

Microsoft.Data.SqlClient implements provider-independent types from System.Data.Common, including DbConnection, DbCommand, DbDataReader, and DbTransaction. It also provides SQL Server-specific APIs such as:

• SqlBulkCopy
• SqlBatch
• SqlConnectionStringBuilder
• SqlConfigurableRetryFactory
• SqlDependency
• SQL Server-specific authentication, encryption, and data type support

For guidance on choosing provider-independent or SqlClient-specific APIs, see ADO.NET architecture with Microsoft.Data.SqlClient.

Relationship to System.Data.SqlClient

System.Data.SqlClient is the older provider that ships with .NET Framework and earlier .NET releases. Microsoft.Data.SqlClient uses many of the same type names, but it has different packages, namespaces, defaults, features, and support policies.

Don't reference both providers in new application code. Types with the same name from the two packages aren't interchangeable. A System.Data.SqlClient.SqlConnection, for example, can't be passed where a Microsoft.Data.SqlClient.SqlConnection is required.

Migration usually starts by adding the Microsoft.Data.SqlClient package and changing namespace references, but you must also review connection encryption, parameters, configuration, transitive dependencies, and runtime behavior. Follow Migrate from System.Data.SqlClient to Microsoft.Data.SqlClient before you deploy.

Version compatibility

The driver package version is independent of the application's .NET version and the database engine version. Check all three:

For current matrices, see SqlClient driver support lifecycle.

Version-specific changes

Driver releases can add APIs, move optional dependencies, and change secure defaults. Review changes before every minor or major update.

Examples include:

• Version 4.0 changed Encrypt to default to true.
• Version 5.0 introduced SqlConnectionEncryptOption and Encrypt=Strict for TDS 8.0.
• Version 5.2 introduced SqlBatch on supported modern .NET targets.
• Version 7.0 moved driver-provided Microsoft Entra authentication into Microsoft.Data.SqlClient.Extensions.Azure.

See What's new in Microsoft.Data.SqlClient for release-note links and an upgrade summary.

Related namespaces and packages

Some features use types outside the main namespace or optional packages.

Don't infer package requirements from a namespace alone. Follow the feature article and the NuGet package dependency information for the driver version you use.

Related content

• Install, update, and deploy Microsoft.Data.SqlClient
• Migrate from System.Data.SqlClient to Microsoft.Data.SqlClient
• What's new in Microsoft.Data.SqlClient
• Microsoft.Data.SqlClient release notes