C ++ DAL - return link or padding in link

Question

[EDIT 1 - added third pointer syntax (thanks Alex)]

Which method do you prefer for DAL and why from it:

Car& DAL::loadCar(int id) {}
bool DAL::loadCar(int id, Car& car) {}
Car* DAL::loadCar(int id) {}

If the first method of the car cannot be found, null is returned; the second method returns false.

The second method would create a Car object on the heap and populate the data requested from the database. Presumably (my C ++ is very rusty), which will mean the code line by line:

Car& DAL::loadCar(int id)
{
    Car *carPtr = new Car();
    Car &car= *carPtr;
    car.setModel(/* value from database */);
    car.setEngineSize(/* value from database */);
    // etc
    return car;
}

thanks

Answer 1

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Car myCar = dal.loadCar( id );

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Edit2: . , , , .

Car DAL::loadCar(int id);

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Answer 2

, Car * LoadCar(), NULL, . , ( ), .