c# - what is the query of sql database connection -

i want connect c# project sql database.
query have follow??

using(sqlconnection connection = new sqlconnection(connectionstring)) {     connection.open(); } 

i use this, not working

try this

namespace town {     class clsconnection     {         string connection = @"data source=server name;initial catalog=databasename;integrated security=true";          public sqlconnection getconnection()         {             sqlconnection sql = new sqlconnection(connection);             sql.open();             return sql;         }     } }