[odb-users] Multiple pointer types in a single object

[Boris Kolpackov]

Hi Thomas,

Szumowski, Thomas <thomas.szumowski at lmco.com> writes:

> Suppose I have a class that requires relationships to two different
> objects. One relationship requires weak_ptr, and one requires shared_ptr.
> Is this possible?

Yes, this is not a problem.


> We noticed one can assign the pointer type at the object level,
> ("#pragma db object pointer"), but what if we want multiple pointer
> types in a single object? e.g (for example purpose only)
> 
> class employee {
> ...
> shared_ptr<employer> e;
> weak_ptr<project> p;
> }
> 
> Is this possible?

Yes, the object pointer that is assigned via db pointer pragma or
using the --default-pointer option is what is used to return such
objects from load(), etc. It should normally be a shared_ptr. But
in object relationships you can use any pointer type as long as
it can be created from the object pointer. So weak_ptr should not
cause any problem here. You can even have something like this:

class employee 
{
  shared_ptr<employer> current_employer;
  weak_ptr<employer> previous_employer;
}

Boris