Dear Friend,
I am sorry that I can't explain all things you want cause it's the whole concept of ADO.net.I want to give you an advise that pls read Ado.net chapter to understand
......DataSet
......DataAdapter
......DataProvider(OleDb.net and SQL Server .net providers)
and others ...


Sample connection string with SqlConnection From MS C#.net Ebook
////
SqlConnection conn = new SqlConnection();
string sConnString = "data source=(local);initial catalog=pubs;" +
"user id=sa;password=;";
conn.ConnectionString = sConnString;
//


Sample datareader From MS C#.net Ebook


SqlCommand cmd = new SqlCommand("SELECT * FROM authors");



SqlDataReader rdr = cmd.ExecuteReader();

While(rdr.Read())
{
string firstCol = rdr.GetSqlString(0);
int secondCol = rdr.GetSqlInt32(1);
//Get other columns using the Get methods
//and take action.

}


a lot...


I am sorry that I can't explain the whole chapter.Pls read Ado.net chapter ....




Enjoy it