.NET Framework Data Provider for SQL Server connection strings

SQL Server 2019

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

LocalDB named instance via the named pipes pipe name

The Server=(localdb) syntax is not supported by .NET framework versions before 4.0.2. However the named pipes connection will work to connect pre 4.0.2 applications to LocalDB instances.

Server=np:\\.\pipe\LOCALDB#F365A78E\tsql\query;

Executing SqlLocalDB.exe info MyInstance will get you (along with other info) the instance pipe name such as "np:\\.\pipe\LOCALDB#F365A78E\tsql\query".

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Using an User Instance on a local SQL Server Express instance

The User Instance functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer.

Data Source=.\SQLExpress;Integrated Security=true;AttachDbFilename=C:\MyFolder\MyDataFile.mdf;User Instance=true;

To use the User Instance functionality you need to enable it on the SQL Server. This is done by executing the following command: sp_configure 'user instances enabled', '1'. To disable the functionality execute sp_configure 'user instances enabled', '0'.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

Always Encrypted with secure enclaves

Data Source=myServer;Initial Catalog=myDB;Integrated Security=true;Column Encryption Setting=enabled;Enclave Attestation Url=http://hgs.bastion.local/Attestation;

Always Encrypted in System.Data.SqlClient is available only for .NET Framework, not .NET Core. To use Always Encrypted in .NET Core switch to Microsoft.Data.SqlClient (NuGet-package).

SQL Server 2017

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

LocalDB named instance via the named pipes pipe name

The Server=(localdb) syntax is not supported by .NET framework versions before 4.0.2. However the named pipes connection will work to connect pre 4.0.2 applications to LocalDB instances.

Server=np:\\.\pipe\LOCALDB#F365A78E\tsql\query;

Executing SqlLocalDB.exe info MyInstance will get you (along with other info) the instance pipe name such as "np:\\.\pipe\LOCALDB#F365A78E\tsql\query".

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Using an User Instance on a local SQL Server Express instance

The User Instance functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer.

Data Source=.\SQLExpress;Integrated Security=true;AttachDbFilename=C:\MyFolder\MyDataFile.mdf;User Instance=true;

To use the User Instance functionality you need to enable it on the SQL Server. This is done by executing the following command: sp_configure 'user instances enabled', '1'. To disable the functionality execute sp_configure 'user instances enabled', '0'.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 2016

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

LocalDB named instance via the named pipes pipe name

The Server=(localdb) syntax is not supported by .NET framework versions before 4.0.2. However the named pipes connection will work to connect pre 4.0.2 applications to LocalDB instances.

Server=np:\\.\pipe\LOCALDB#F365A78E\tsql\query;

Executing SqlLocalDB.exe info MyInstance will get you (along with other info) the instance pipe name such as "np:\\.\pipe\LOCALDB#F365A78E\tsql\query".

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Using an User Instance on a local SQL Server Express instance

The User Instance functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer.

Data Source=.\SQLExpress;Integrated Security=true;AttachDbFilename=C:\MyFolder\MyDataFile.mdf;User Instance=true;

To use the User Instance functionality you need to enable it on the SQL Server. This is done by executing the following command: sp_configure 'user instances enabled', '1'. To disable the functionality execute sp_configure 'user instances enabled', '0'.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 2014

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

LocalDB named instance via the named pipes pipe name

The Server=(localdb) syntax is not supported by .NET framework versions before 4.0.2. However the named pipes connection will work to connect pre 4.0.2 applications to LocalDB instances.

Server=np:\\.\pipe\LOCALDB#F365A78E\tsql\query;

Executing SqlLocalDB.exe info MyInstance will get you (along with other info) the instance pipe name such as "np:\\.\pipe\LOCALDB#F365A78E\tsql\query".

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Using an User Instance on a local SQL Server Express instance

The User Instance functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer.

Data Source=.\SQLExpress;Integrated Security=true;AttachDbFilename=C:\MyFolder\MyDataFile.mdf;User Instance=true;

To use the User Instance functionality you need to enable it on the SQL Server. This is done by executing the following command: sp_configure 'user instances enabled', '1'. To disable the functionality execute sp_configure 'user instances enabled', '0'.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 2012

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

LocalDB named instance via the named pipes pipe name

The Server=(localdb) syntax is not supported by .NET framework versions before 4.0.2. However the named pipes connection will work to connect pre 4.0.2 applications to LocalDB instances.

Server=np:\\.\pipe\LOCALDB#F365A78E\tsql\query;

Executing SqlLocalDB.exe info MyInstance will get you (along with other info) the instance pipe name such as "np:\\.\pipe\LOCALDB#F365A78E\tsql\query".

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 2008

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Using an User Instance on a local SQL Server Express instance

The User Instance functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer.

Data Source=.\SQLExpress;Integrated Security=true;AttachDbFilename=C:\MyFolder\MyDataFile.mdf;User Instance=true;

To use the User Instance functionality you need to enable it on the SQL Server. This is done by executing the following command: sp_configure 'user instances enabled', '1'. To disable the functionality execute sp_configure 'user instances enabled', '0'.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 2005

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Attach a database file, located in the data directory, on connect to a local SQL Server Express instance

Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf;Database=dbname;Trusted_Connection=Yes;

Why is the Database parameter needed? If the named database have already been attached, SQL Server does not reattach it. It uses the attached database as the default for the connection.

Database mirroring

If you connect with ADO.NET or the SQL Native Client to a database that is being mirrored, your application can take advantage of the drivers ability to automatically redirect connections when a database mirroring failover occurs. You must specify the initial principal server and database in the connection string and the failover partner server.

Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;Initial Catalog=myDataBase;Integrated Security=True;

There is ofcourse many other ways to write the connection string using database mirroring, this is just one example pointing out the failover functionality. You can combine this with the other connection strings options available.

Using an User Instance on a local SQL Server Express instance

The User Instance functionality creates a new SQL Server instance on the fly during connect. This works only on a local SQL Server instance and only when connecting using windows authentication over local named pipes. The purpose is to be able to create a full rights SQL Server instance to a user with limited administrative rights on the computer.

Data Source=.\SQLExpress;Integrated Security=true;AttachDbFilename=C:\MyFolder\MyDataFile.mdf;User Instance=true;

To use the User Instance functionality you need to enable it on the SQL Server. This is done by executing the following command: sp_configure 'user instances enabled', '1'. To disable the functionality execute sp_configure 'user instances enabled', '0'.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 2000

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

SQL Server 7.0

Trusted Connection from a CE device

A Windows CE device is most often not authenticated and logged in to a domain but it is possible to use SSPI or trusted connection and authentication from a CE device using this connection string.

Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;User ID=myDomain\myUsername;Password=myPassword;

Note that this will only work on a CE device.

Specifying packet size

Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096;

By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead. The default value of 8192 might cause Failed to reserve contiguous memory errors as well, read more here.

Azure SQL Database

Standard

Server=tcp:myserver.database.windows.net,1433;Database=myDataBase;User ID=mylogin@myserver;Password=myPassword;Trusted_Connection=False;Encrypt=True;

Use 'mylogin@myserver' for the User ID parameter.

With MARS enabled

Server=tcp:myserver.database.windows.net,1433;Database=myDataBase;User ID=mylogin@myserver;Password=myPassword;Trusted_Connection=False;Encrypt=True;MultipleActiveResultSets=True;

Integrated Windows authentication with an Azure AD identity

To connect with integrated authentication and Azure AD identity, Authentication should be set to Active Directory Integrated. The client must be running on a machine joined to the domain.

Server=tcp:myserver.database.windows.net,1433;Authentication=Active Directory Integrated;Database=mydatabase;

Note! You cannot use Integrated Security=True/SSPI when connecting to Azure SQL Database.