[odb-users] Containers of containers not detected

Andrew Cunningham andrew at a-cunningham.com
Fri Apr 29 17:20:51 EDT 2016

Hi Boris,

It would be great if the ODB compiler could detect "containers of
containers" and throw an error.

I am using a std::map<key, value> and the "value" object is holding a
std::vector<unsigned char>.
The ODB compiler accepts that quite happily, but this violates "container
of containers" AFAIK.

But surprisingly, if the std::vector<unsigned char> is declared #pragma db
type("BLOB") then the code actually functions correctly and loads the
nested data container.
If the BLOB #pragma is removed , then the std::vector data is not loaded

So it seems I have unintentionally backed myself into a corner.
- Is the "container of containers" a hard limitation that will remain in
future versions of ODB?
- Is the fact that using a BLOB makes the code work just blind good luck?


#pragma db value
class ValueObject

#pragma db type("BLOB")
    std::vector< unsigned char >    vec_;

#pragma db object
class Other

    std::map<int,ValueObject> aMap_;


I'll send you a project that illustrates this.

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