Unfortunately I believe MSVC doesn't support %llu as a format specifier.  We do have PRIu64 if that's what you want to use.

In some senses it's almost better to write it as a datetime string - at least then when you look in the database you know what you're looking at?

Still, this is something that can be looked into later, as long as there's a plan in place.

@opdenkamp any opinion?