Wt

https://github.com/emweb/wt/blob/d9dbba89f50763e00c7127916c91e2fb44e16280/src/Wt/Dbo/StdSqlTraits.h#L106-L128

Status: Closed

So chrono::time_point works but chrono::seconds doesnt:

include/Wt/Dbo/Field_impl.h:48:35: error: ‘type’ is not a member of ‘Wt::Dbo::sql_value_traits<std::chrono::duration<long int>, void>’
   return sql_value_traits<V>::type(session.connection(false), size_);
          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

chrono::time_point is created as text column. I expected it to be timestamp/uint.

P.S. Sorry for flood but I can't edit comments.

When I try to specialize that trait I get error:

error: no matching function for call to ‘Wt::Dbo::SqlStatement::getResult(int&, std::chrono::seconds*)’
     if (statement->getResult(column, &v)) {
                                        ^
In file included from /home/i/cpp/.../src/storage/wtDboCustomTypes.h:11:0,
                 from /home/i/cpp/.../src/storage/wtDboCustomTypes.cpp:9:
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:129:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, std::__cxx11::string*, int)
   virtual bool getResult(int column, std::string *value, int size) = 0;
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:129:16: note:   candidate expects 3 arguments, 2 provided
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:135:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, short int*)
   virtual bool getResult(int column, short *value) = 0;
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:135:16: note:   no known conversion for argument 2 from ‘std::chrono::seconds* {aka std::chrono::duration<long int>*}’ to ‘short int*’
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:141:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, int*)
   virtual bool getResult(int column, int *value) = 0;
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:141:16: note:   no known conversion for argument 2 from ‘std::chrono::seconds* {aka std::chrono::duration<long int>*}’ to ‘int*’
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:147:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, long long int*)
   virtual bool getResult(int column, long long *value) = 0;
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:147:16: note:   no known conversion for argument 2 from ‘std::chrono::seconds* {aka std::chrono::duration<long int>*}’ to ‘long long int*’
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:153:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, float*)
   virtual bool getResult(int column, float *value) = 0;
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:153:16: note:   no known conversion for argument 2 from ‘std::chrono::seconds* {aka std::chrono::duration<long int>*}’ to ‘float*’
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:159:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, double*)
   virtual bool getResult(int column, double *value) = 0;
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:159:16: note:   no known conversion for argument 2 from ‘std::chrono::seconds* {aka std::chrono::duration<long int>*}’ to ‘double*’
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:165:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, std::chrono::_V2::system_clock::time_point*, Wt::Dbo::SqlDateTimeType)
   virtual bool getResult(int column, std::chrono::system_clock::time_point *value,
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:165:16: note:   candidate expects 3 arguments, 2 provided
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:172:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, std::chrono::duration<int, std::ratio<1l, 1000l> >*)
   virtual bool getResult(int column, std::chrono::duration<int, std::milli> *value)
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:172:16: note:   no known conversion for argument 2 from ‘std::chrono::seconds* {aka std::chrono::duration<long int>*}’ to ‘std::chrono::duration<int, std::ratio<1l, 1000l> >*’
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:179:16: note: candidate: virtual bool Wt::Dbo::SqlStatement::getResult(int, std::vector<unsigned char>*, int)
   virtual bool getResult(int column, std::vector<unsigned char> *value,
                ^~~~~~~~~
/home/i/cpp/.../cmake-build-debug/external-projects/installed/include/Wt/Dbo/SqlStatement.h:179:16: note:   candidate expects 3 arguments, 2 provided
                                        ^

#include <Wt/Dbo/SqlTraits.h>
#include <Wt/Dbo/SqlConnection.h>
#include <Wt/Dbo/SqlStatement.h>
#include <chrono>

namespace Wt { namespace Dbo {

template<>
class WTDBO_API sql_value_traits<std::chrono::seconds, void>
{
    static const bool specialized = true;

    static std::string type(SqlConnection *conn, int size);
    static void bind(const std::chrono::seconds& v, SqlStatement *statement, int column, int size);
    static bool read(std::chrono::seconds& v, SqlStatement *statement, int column, int size);
};

}}

namespace Wt { namespace Dbo {

std::string sql_value_traits<std::chrono::seconds>::type(SqlConnection *conn, int size)
{
    return conn->dateTimeType(SqlDateTimeType::Time);
}

void sql_value_traits<std::chrono::seconds>::bind(
    const std::chrono::seconds& v,
    SqlStatement *statement,
    int column,
    int size
) {
    if (v == std::chrono::seconds::zero()) {
        statement->bindNull(column);
    } else {
        statement->bind(column, v);
    }
}

bool sql_value_traits<std::chrono::seconds>::read(
    std::chrono::seconds& v,
    SqlStatement *statement,
    int column,
    int size
) {
    if (statement->getResult(column, &v)) {
        return true;
    } else {
        v = std::chrono::seconds::zero();
        return false;
    }
}

}}

https://github.com/emweb/wt/pull/122

std::chrono::seconds is not supported, but std::chrono::duration<int, std::milli> is, which of course does have a shorter range. I'm not really sure why duration<int, std::milli> was chosen, I'll have to look into that.