[odb-users] polymorphic inheritance, typeid, odb::object_not_persistent

[MM]

On 22 July 2015 at 16:46, MM <finjulhich at gmail.com> wrote:

> On 22 July 2015 at 15:43, Boris Kolpackov <boris at codesynthesis.com> wrote:
>
>> Hi,
>>
>> MM <finjulhich at gmail.com> writes:
>>
>> > Within the same transaction, I do successfully load 11(all) of the
>> > 'sometype':
>> > I get raw pointers from the load() calls (same as above), and I own
>> these
>> > pointers with a boost::ptr_vector.
>> > _After_ the 'sometype' are loaded, I, then, load the Base items. But
>> that
>> > fails.
>>
>> What if you try to load D1..D10 using load() rather than query(),
>> specifying either Base or the concrete types (both should work).
>> This way you can narrow it down to which one fails to load (if
>> any; it can also be that load() will work and there is something
>> special about query()).
>>
>>
>> > Am I breaking the relationship for odb to connect the dots somehow?
>>
>> Not that I can see.
>>
>>
>> > Is there some sort of debugging I can trigger to detect the issue?
>>
>> Yes, in fact, enabling statement tracing in such situations can be
>> very helpful. Try:
>>
>> t.tracer (stderr_tracer);
>>
>> This way we will at least know where exactly things go south.
>>
>> Boris
>>
>
> The first load succeeds for 'sometype' as mentioned before, and the sql
> queries are traced out.
>
> Then, the code that fails:
>
> {
>       auto res = db.query<NS::Base>();
>       std::size_t cnt = 0u;
>       for (auto i=std::begin(res); i!=std::end(res); ++i, ++cnt)
>         some_function( i.load() );
>       std::cout<<" "<<cnt<<" items loaded" << std::endl;
> }
>
> yields these SQL stmts:
>
> SELECT "Base"."name", "Base"."typeid", "Base"."cal" FROM "Base"
> SELECT "OtherTable"."name" FROM "OtherTable" WHERE "OtherTable"."name"=?
> object not persistent
> terminate called after throwing an instance of 'odb::object_not_persistent'
>   what():  object not persistent
>
> some of the Base.cal are NULL in the database.
>
> obviously I would need to change my
>
> #pragma db member(Base::cal_) get(&this.sometype())  set(this.sometype
> (*(?)))
>
> How to say: if NULL in the database, then don't sent the cal member?
>

I have put in a if statement in the set() modifier.

Indeed the cal field was pointing to a inexisting entry in the other table.
I need to review the referential integrity items about sqlite in the odb
manual.

thanks,