How to arrange the logic of adding data to the database with checking for weekends and holidays?

Question

PHP

I am making a time sheet, it is necessary to count the number of hours of "processing" that are paid at a different rate. This tariff is x2 on weekends and holidays in the database, you need to do 2 columns, working hours and processing hours.
And for convenience, enter data in one field on the frontend in the form, then if the date of adding to the database == day off, then write all the data in the processing column. Also for the holiday
. If it's not a day off, but more than 8 hours are worked, then write 8 in the hours and the rest in the processing database.
before that, everything seems to be simple, but now if the day off means a shortened day, then we write 7 hours to work and the rest to processing
and the most important question: how to find out that the date, for example 2019-03-22, is a day off or a holiday?Means it is necessary to do the separate table with these dates for comparison? I do not understand the principle to the end, who will tell you the logic of how to do it right?

Answer 1

Well, you can find out the day off by the day of the week, but the holidays will have to be stored somewhere in the database, or look for a ready-made API on this topic, or find the API of some service where you can pull out the holidays.
Here and there