I would always handle this with a calendar table, personally. There's a lot more than just holiday dates you can include: Comments on what the holiday is (or other comments on a per-day basis), day of week/day of year/day of quarter/etc for ease and performance of writing reporting queries, and perhaps other things I haven't thought of yet... It can be queried and updated easily by anyone who needs to (you can write an app to maintain it), and it's entirely flexible.