LocalDB automatic instance using Microsoft.Data.SqlClient

Connection string

This Microsoft SqlClient Data Provider for SQL Server connection string can be used for connections to SQL Server 2019, SQL Server 2017, SQL Server 2016, SQL Server 2014 and SQL Server 2012.

Server=(localdb)\v11.0;Integrated Security=true;

The first connection to LocalDB will create and start the instance, this takes some time and might cause a connection timeout failure. If this happens, wait a bit and connect again.