get data from DB nopcommerce

How does nopcommerce get data to display from the data base.
I use code like this

  command.Connection = Myconn
        command.CommandText = "  SELECT * FROM...
        da.SelectCommand = command
        da.Fill(ds, "thread")

but I cant see  how nopCommerce can get data from th DB as i dont see code like this?

i want to display some data from the db.