I saw no benefit in storing two copies. That’s recipe for problems - e.g. “update” code that doesn’t update both, or somehow updates them differently (which one is right?). You can probably have t-sql or some “check” constraint to enforce equivalence, but ... why?
For most practical uses, an ISO8601 textual representation is as good, though a little less space efficient.
I saw no benefit in storing two copies. That’s recipe for problems - e.g. “update” code that doesn’t update both, or somehow updates them differently (which one is right?). You can probably have t-sql or some “check” constraint to enforce equivalence, but ... why?
For most practical uses, an ISO8601 textual representation is as good, though a little less space efficient.