[odb-users] reuse inheritance with templated base class

[Boris Kolpackov]

Hi Marcel,

Marcel Nehring <mne at qosmotec.com> writes:

> #pragma db object optimistic
> template <class T>
> class Base

ODB does not support persistent class templates. The persistent data
(m_id and m_version in your case) rarely depends on the template
argument (it doesn't in your case) so what you can do is split your
base into two classes:

#pragma db object optimistic
class BaseData
{
  #pragma db id auto
  long long m_id;

  #pragma db version
  const unsigned long long m_version;
};

// Note: not persistent object
template <class T>
class Base 
{
  ...
};

#pragma db object
class Derived : public Base<Derived>, public BaseData
{
  ...
};

Boris