Some useful links:
Microsoft tool for creating connection strings
ConnectionStrings.com
A connection string is a text string that specifies the parameters needed to access to the Microsoft SQL server database. The following examples show connection strings for the most common configurations:
Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;
This connection string produces the same result as the previous one. It is included here to point out that some connection string keywords have many equivalents.
Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;
Data Source=myServerAddress;Initial Catalog=myDataBase;Integrated Security=SSPI;
This connection string produces the same result as the previous one. It is included here to point out that some connection string keywords have many equivalents.
Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;
The syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.
Server=myServerName\theInstanceName;Database=myDataBase;Trusted_Connection=True;