Not sure if you are joking... But if you aren't I would really recommend you read this excerpt:
Trump’s a great businessman, who financed his rise with money from his father and massive amounts of debt borrowed against the value of his properties. He has filed six bankruptcies, and is still in business only because his banks could not afford to let him go under, and had to accept a partial write-down of his debts. He routinely refuses to pay his workers and contractors his agreed-upon rates, and has been sued more than 3,200 times as a result. He routinely lies about how much money he is actually worth, dumped loads of his own debt on his shareholders, tanking the value of his own company in the process, and would have made a lot more money if he invested in index funds, which doesn’t mean index funds are so great; it means Trump hasn’t managed his money well enough to beat the returns on a conservative investment. American banks won’t loan him any more money, and he remains massively in debt to foreign banks, while estimating his own net worth based on his day-to-day “feelings”. Oh, and most of the businesses to which he has lent his name in the last 10 to 15 years have failed.
So, in conclusion, Trump is an excellent entertainer, a mediocre talent at the business he inherited, and a failure in everything else he's laid a hand to. Business schools don't do case studies of Donald Trump. They look at people like Jack Welch, Sam Walton, Warren Buffet, Carlos Slim, Herbert Dow, etc. People who are famous because others talk about what they did, not because they talk about themselves.