opening a connection to a database...

Basically that is shows connection string of your application with your database.........

What type of database connection are you using? The connection strings vary by driver. Here is some english variable names associated with the connection string file names:

public static string BuildSqlNativeConnStr(string server, string database)
    {
      return string.Format("Data Source={0};Initial Catalog={1};Integrated Security=True;", server, database);
    }
    public static string BuildSqlNativeConnStr(string server, string database, string username, string password)
    {
      return string.Format("Data Source={0};Initial Catalog={1};Integrated Security=False;User Id={2};Password={3};", 
        server, 
        database,
        username,
        password);
    }
    public static string BuildExcelConnectionString(string Filename, bool FirstRowContainsHeaders)
    {
      return string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source='{0}';Extended Properties=\"Excel 8.0;HDR={1};\"",
                          Filename.Replace("'", "''"),
                          FirstRowContainsHeaders ? "Yes" : "No");
    }
    public static string BuildExcel2007ConnectionString(string Filename, bool FirstRowContainsHeaders)
    {
      return string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=\"Excel 12.0;HDR={1}\";",
                            Filename.Replace("'", "''"),
                            FirstRowContainsHeaders ? "Yes" : "No");
    }
    public static string BuildAccessConnectionString(string Filename, string Username, string Password, string DatabasePassword)
    {
      return string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source='{0}';User Id={1};Password={2};Jet OLEDB:Database Password={3};",
                                   Filename.Replace("'", "''"),
                                   Username,
                                   Password,
                                   DatabasePassword);
    }
    public static string BuildAccess2007ConnectionString(string Filename, string DatabasePassword)
    {
      return string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source='{0}';Persist Security Info=False;Jet OLEDB:Database Password={1};",
                                 Filename.Replace("'", "''"),
                                 DatabasePassword);
    }
    public static string BuildODBCConnectionString(string DSN)
    {
      return string.Format("DSN={0}", DSN);
    }

Here is a good place to start; please scroll down the page for explainations of each property.
http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectionstring(VS.71).aspx