Microsoft.Data.SqlClient

Description

Microsoft.Data.SqlClient is the official .NET data provider for Microsoft SQL Server and Azure SQL databases. It provides access to SQL Server and encapsulates database-specific protocols, including Tabular Data Stream (TDS).

This library grew from a union of the two System.Data.SqlClient components which live independently in .NET and .NET Framework. Going forward, support for new SQL Server and Azure SQL features will only be implemented in Microsoft.Data.SqlClient.

Supportability

This package supports:

• .NET Framework 4.6.2+
• .NET 10.0+

The implementation targets net462;net10.0. Reference and unsupported-platform assemblies also retain netstandard2.0; that target does not extend supported driver runtimes.

SqlClient family version validation

This package ships a consumer MSBuild target in build/ and buildTransitive/. NuGet imports it for direct package consumers and transitive PackageReference consumers. After package/reference resolution it compares installed Microsoft.Data.SqlClient.Internal.Logging, Microsoft.Data.SqlClient.Extensions.Abstractions, Microsoft.Data.SqlClient.Extensions.Azure, and Microsoft.Data.SqlClient.AlwaysEncrypted.AzureKeyVaultProvider package versions against the resolved Microsoft.Data.SqlClient package version. Optional packages are not required. Microsoft.SqlServer.Server and native SNI packages are excluded.

Versions must match exactly, including prerelease labels; a mismatch emits the SQLCLIENT001 warning rather than failing the build by default. Upgrade all installed family packages together. Historical extensions numbered 1.0.0 are not mapped to driver 7.0.0/7.0.1. The check uses resolved compile/runtime asset metadata for PackageReference and installed versions in the active packages.config for legacy consumers. A packages.<project-name>.config file takes precedence over packages.config; spaces in the project name are replaced with underscores, matching NuGet. It does not check assembly versions, restore ranges, or API compatibility. Assets missing version metadata and builds without a Microsoft.Data.SqlClient version anchor are skipped. Design-time builds are skipped.

To suppress the warning, set SqlClientEnforceFamilyVersions=false in the consumer project or pass -p:SqlClientEnforceFamilyVersions=false. This disables only this build check; it does not make mixed versions compatible. Excluding the package's build assets also prevents target import. NuGet buildTransitive targets can propagate through project-reference chains when a referenced project consumes Microsoft.Data.SqlClient as a package. A direct project reference to SqlClient's source project does not import its packaged targets, so this check does not enforce in-tree Project-mode versions.

Installation

Install the package via NuGet:

dotnet add package Microsoft.Data.SqlClient

Or via the Package Manager Console:

Install-Package Microsoft.Data.SqlClient

Getting Started

Basic Connection

using Microsoft.Data.SqlClient;

var connectionString = "Server=myserver;Database=mydb;Integrated Security=true;";

using var connection = new SqlConnection(connectionString);
await connection.OpenAsync();

Console.WriteLine("Connected successfully!");

Connecting to Azure

Starting with v7.0, to use Entra ID authentication modes (such as Active Directory Default, Active Directory Managed Identity, Active Directory Interactive, etc.) via connection string keywords, install the Microsoft.Data.SqlClient.Extensions.Azure extension package via NuGet:

dotnet add package Microsoft.Data.SqlClient.Extensions.Azure

Or via the Package Manager Console:

Install-Package Microsoft.Data.SqlClient.Extensions.Azure

This package provides the ActiveDirectoryAuthenticationProvider, which uses Azure.Identity credential types supplied by Azure.Core to handle token acquisition, caching, and credential management.

The authentication registry and SqlAuthenticationInitializer now live in Microsoft.Data.SqlClient.Extensions.Abstractions; existing driver type names are forwarded. SqlAuthenticationProvider.GetProvider and SetProvider work directly without a reflective bridge to the driver. Configuration registrations take precedence over application registrations, which take precedence over discovered Azure defaults.

For explicit registration in trimmed and NativeAOT .NET 10 applications, disable reflective Azure discovery and authentication app.config loading at publish time, then construct and register a provider for each required method before opening connections. Trimmed JIT applications may retain enabled reflection paths when they preserve the configuration infrastructure, handlers, providers, initializers and discovered Azure contracts. Enabled paths report trimming/dynamic-code warnings. They are not removed automatically. The switches Switch.Microsoft.Data.SqlClient.EnableAppConfig and Switch.Microsoft.Data.SqlClient.EnableAzureExtensionDiscovery default to true and are cached on first access. Recoverable initialization failures emit diagnostic guidance through Microsoft.Data.SqlClient.EventSource (Informational level, Trace keyword 0x2). Recoverable bootstrap failures do not block explicit application registration or lookup of usable registrations. Failed explicit methods cannot fall back to old/default providers; initializer failure prevents defaults for otherwise-unregistered methods. Register a provider as a workaround, or correct the cause and restart the application. Fatal bootstrap failures propagate without being cached by the registry; later access can retry and repeat side effects if execution continues. Detailed activation causes are not attached to the connection exception.

With this package reference, you can continue to use Entra ID authentication modes directly in your connection string:

// Active Directory Default — uses DefaultAzureCredential (Managed Identity, Azure CLI, Visual Studio, etc.)
var connectionString = "Server=myserver.database.windows.net;Database=mydb;Authentication=Active Directory Default;";

using var connection = new SqlConnection(connectionString);
await connection.OpenAsync();

Execute a Query

using Microsoft.Data.SqlClient;

var connectionString = "Server=myserver;Database=mydb;Integrated Security=true;";

using var connection = new SqlConnection(connectionString);
await connection.OpenAsync();

using var command = new SqlCommand("SELECT Id, Name FROM Customers", connection);
using var reader = await command.ExecuteReaderAsync();

while (await reader.ReadAsync())
{
    Console.WriteLine($"Id: {reader.GetInt32(0)}, Name: {reader.GetString(1)}");
}

Parameterized Query

using Microsoft.Data.SqlClient;

var connectionString = "Server=myserver;Database=mydb;Integrated Security=true;";

using var connection = new SqlConnection(connectionString);
await connection.OpenAsync();

using var command = new SqlCommand("SELECT * FROM Customers WHERE Id = @id", connection);
command.Parameters.AddWithValue("@id", customerId);

using var reader = await command.ExecuteReaderAsync();
// Process results...

Using Transactions

using Microsoft.Data.SqlClient;

using var connection = new SqlConnection(connectionString);
await connection.OpenAsync();

using var transaction = connection.BeginTransaction();

try
{
    using var command = new SqlCommand("INSERT INTO Orders (CustomerId, Total) VALUES (@customerId, @total)", connection, transaction);
    command.Parameters.AddWithValue("@customerId", customerId);
    command.Parameters.AddWithValue("@total", orderTotal);
    
    await command.ExecuteNonQueryAsync();
    await transaction.CommitAsync();
}
catch
{
    await transaction.RollbackAsync();
    throw;
}

Key Features

Commonly Used Types

Microsoft.Data.SqlClient.SqlConnection
Microsoft.Data.SqlClient.SqlCommand
Microsoft.Data.SqlClient.SqlDataReader
Microsoft.Data.SqlClient.SqlParameter
Microsoft.Data.SqlClient.SqlTransaction
Microsoft.Data.SqlClient.SqlException
Microsoft.Data.SqlClient.SqlParameterCollection
Microsoft.Data.SqlClient.SqlClientFactory
Microsoft.Data.SqlClient.SqlBulkCopy
Microsoft.Data.SqlClient.SqlConnectionStringBuilder

Authentication Methods

Note: To use Entra ID authentication modes (such as Active Directory Default, Active Directory Managed Identity, Active Directory Interactive, etc.) via connection string keywords, install the Microsoft.Data.SqlClient.Extensions.Azure extension package.

Encryption Modes

SNI (SQL Server Network Interface)

Two implementations are available:

• Native SNI: Windows-only, provided via Microsoft.Data.SqlClient.SNI (.NET Framework) or Microsoft.Data.SqlClient.SNI.runtime (.NET on Windows)
• Managed SNI: Cross-platform managed implementation, used by default on Unix platforms

Documentation

• Microsoft.Data.SqlClient Documentation
• Connection String Syntax
• Connection Pooling
• Always Encrypted
• Entra ID Authentication

Release Notes

Release notes are available at: https://go.microsoft.com/fwlink/?linkid=2090501

Migrating from System.Data.SqlClient

If you're migrating from System.Data.SqlClient, see the porting cheat sheet for guidance.

Key changes:

1. Change namespace from System.Data.SqlClient to Microsoft.Data.SqlClient
2. Update package reference to Microsoft.Data.SqlClient
3. Review connection string defaults (e.g., Encrypt=Mandatory is now the default)

License

This package is licensed under the MIT License.

Related Packages

• Microsoft.Data.SqlClient.Extensions.Azure - Entra ID authentication provider using Azure.Core credentials
• Microsoft.Data.SqlClient.AlwaysEncrypted.AzureKeyVaultProvider - Azure Key Vault integration for Always Encrypted
• Microsoft.SqlServer.Server - SQL CLR UDT support
• Microsoft.Data.SqlClient.SNI - Native SNI for .NET Framework
• Microsoft.Data.SqlClient.SNI.runtime - Native SNI runtime for .NET on Windows