[odb-users] unable to map C++ type '::std::chrono::duration< double >'

[Karen Arutyunov]

> The variable type is std::chrono::duration, that's why I want to have it
> also in the database. I'm just asking if it's possible, not if it's the
> best way to represent the time duration/time point.

You can probably use the type mapping.

In our build2 toolchain project we use it for mapping timestamp (aka 
std::chrono::system_clock::time_point) to uint64_t as a number of 
nanoseconds from epoch:

   #pragma db map type(timestamp) as(uint64_t)                 \
     to(std::chrono::duration_cast<std::chrono::nanoseconds> ( \
          (?).time_since_epoch ()).count ())                   \
     from(brep::timestamp (                                    \
       std::chrono::duration_cast<brep::timestamp::duration> ( \
         std::chrono::nanoseconds (?))))

For more details see 
https://git.build2.org/cgit/brep/tree/libbrep/common.hxx#n107