Thread

1. beybol · 1790591768 · focus · HN ↗

   I don't rely on time calculations at the database level. I handle them in the application based on UTC time stored in the database and the user's time zone. This shifts the problem to the application code, where I can control it precisely and make conscious decisions about how to handle specific business requirements, such as when a day ends or how to deal with events across different time zones. It also makes it possible to properly test all cases with unit tests.

   1. ahoka · 1790592162 · focus · HN ↗

      I've seen a product where they used UTC to store opening hours. They had to rewrite all dates via a script twice a year.

      1. GJim · 1790592274 · focus · HN ↗

         Why would the dates need rewriting?

         1. sokoloff · 1790593756 · focus · HN ↗

            I suspect they meant more generally “the date&time field”, but a store in Boston that opens at 7:30 AM and closes at 7:30 PM Eastern time (ET) closes on different UTC date than it opens when ET is EST but opens and closes on the same date when ET is EDT, so it’s plausible that the dates actually needed to be updated.
         2. ahoka · 1790772590 · focus · HN ↗

            Daylight saving changed the UTC time, because opening hours were always in local time.

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