When you go to connect your .NET Framework applications to SQL Server, one of the most essential ingredients is the connection string. The connection string tells the application how to connect to the target SQL Server instance. To do this, the connection string typically provides the name of the server and the database as well as authentication information.
Even newer technologies like the Entity Framework (EF) use ADO.NET under the covers to connect to SQL Server, so they need connection strings too. In this slideshow I show you several handy example SQL Server connection strings that can be used for a variety of situations.