There are 3 SQL Server database instance in most local machines. These are SQL Server Express instances that mainly useful for developers so they don’t have to install any SQL Server instance to get a project up and running. They are:
- <machine_name>\SQLEXPRESS or .\SQLEXPRESS
For example: “stack247\SQLEXPRESS”, or simply “.\SQLEXPRESS”.
This is older version of SQL Server Express, 2008 to be precise. It’s also installed when you install Visual Studio 2010.
- (LocalDB)\v11.0 or (LocalDB)\v11.1
Comes with SQL Server 2012 or Visual Studio 2012. This is a newer version of SQL Server Express, or as the folks at SQL Express team call it, an improved SQL Express. The official name is SQL Express LocalDB
Mainly used as default database by SQL Data Tools to host sandbox databases for your Database projects. Just like SQL Express LocalDB, it also comes with SQL Server 2012 or Visual Studio 2012.