Database connection with C#

I have read several articles here I leave the links:(I hope you like)



http://www.codeproject.com/KB/database/sql_in_csharp.aspx
http://msdn.microsoft.com/en-us/library/s4yys16a(VS.71).aspx
http://en.csharp-online.net/Working_with_Data%E2%80%94Connecting_to_a_SQL_Server_Database
http://www.jonasjohn.de/snippets/csharp/sql-connection-example.htm
http://infynet.wordpress.com/2010/09/24/database-connection-with-c/