The small one is the data cable. Here's one I would buy:
The other is the power connection but on most PCs there are spare SATA power cords coming from the PSU. If you ran out, look for extra 4 Pin Molex connections then get an adapter like this:
I am trying to find a computer part but none of my searches come up with what I am looking for. I am referring to the "cables" - (probably not the right term) that come from the motherboard to the hard drive. There are 2 of them: one has 5 colored wires and the other is a slim flat cable with a smaller connection into the hard drive.I am assuming that the 5 wired one is the power cable and the other is the data cable. It this one that I need the right nomenclature for because I need to purchase one so I can add another hard drive. The5 wired one has another connector.