Adding oil such as Olive Oil to the pasta can and does prevent the water from boiling over which prevents the pasta from sticking.
But when you add oil to the water when cooking pasta it can actually prevent the pasta sauce from sticking to the pasta.
So the oil added to the water when cooking pasta can actually do more harm than good but it will still be fine to eat but the pasta sauce just won't stick to the pasta properly.
If you just constantly stir the pasta and avoid the water boiling over then the pasta should cook just fine without sticking.