Ragu is not the same as bolognese.
Ragu is a general term for a meat based Italian sauce.
And Bolognese is a specific type of ragu sauce from the city of Bologna, which is characterized by it's fine dice, slow cooking and ingredients like milk, white wine, tomato paste, pancetta, pork and beef.
The difference between bolognese and ragu is that bolognese has a rich and creamy texture which is achieved through the addition of milk or sometimes cream and finely chopped or ground meat which is often a combination of beef and pork.
Ragu is a broader term that refers to a wide variety of meat based sauces and some contain larger pieces of meat and may not have any cream or milk.
Ragu is basically a general term for Italian meat based sauces and is often served with pasta.
Ragu also can vary greatly depending on the region and family recipe and uses different types of meat such as game meat, poultry, pork or beef as well as vegetables and can also vary in it's cooking method.
Some ragu sauces are also tomato based and others are white ragu "ragu in bianco" without tomatoes.
Ragu also often uses red wine in it's preparation.
Bolognese is a specific type of ragu sauce that originated in Bologna, Italy.
Bolognese traditionally includes the ingredients such as soffritto, onion, celery and carrot, ground beef and or pork, white wine and a small amount of tomato paste along with cream or milk.
Bolognese also has a creamy, rich and velvety texture which is achieved through the addition of milk or cream.
Bolognese often uses finely chopped or ground meat instead of large chunks of meat and white wine is also traditionally used in Bolognese sauce.