Breaking Changes to LocalDB.
Applies to: Microsoft SQL Server 2014.
 
SQL Server 2014 LocalDB can be downloaded from 
here.
To install SQL Server 2014, you just need to follow these steps:


 

 

 

 
Now that we have installed LocalDB, let's try to connect to the automatic 
instance created. On SQL Server 2012, we used "(localdb)\v11.0" as instance 
name, so we can assume that now we should use "(localdb)\v12.0" as server name 
to connect, but doing that we received the following error:
 

 
Cannot connect lo (LocalDB)\v12.0.
Additional information:
A network-related or instance-specific error occurred while establishing a 
connection to SQL Server.
The server was not found or was not accessible. Verify that the instance name is 
correct and that
SQL Server is configured to allow remote connections. (provider: SQL Network 
Interfaces, error: 50 - 
Local Database Runtime error occurred. The specified LocalDB instance does not 
exist.
) (Microsoft SQL Server)
On SQL Server 2014, The SQL Server team created "mssqllocaldb" as the default 
name for the automatic LocalDB instance. The name of the automatic LocalDB 
instance is no longer related to SQL Server version number (v11.0 = SQL Server 
2012, v12.0 = SQL Server 2014). Thus, we should use "(localdb)\mssqllocaldb" as 
server name to connect to LocalDB automatic instance on SQL Server 2014, as 
shown below.

As you may have noticed, we used SQL Server 2012 Management Studio to connect to 
the SQL Server 2014 LocalDB instance.
 

To learn more about LocalDB, please click 
here.