what are the advantage and disadvantage

what are the advantage and disavantage of unix and oracle? which is better and what are the applications for each? which one is better and have a better paying jobs? what are the length of time study them both? i one to study both but i don’t know which one to choose to study first…help me …which one will be earlier at first…..? what is the future for this two programmings? are they powerful for tomorrow software egineering and much much more others?