Rails model - check if a DateTime object is within a day

Question

I have a model ExchangeRates which has a field time of type DateTime . I want to search for an exchange rate from the same day. I tried in the following manner:

  per = ExchangeRates.find_by(time: er.time.beginning_of_day..er.time.end_of_day)

However, this doesn't return an ExchangeRate object from the same day. How could I correct this?

Answer 1

You may be better served attempting this with a where as follows:

per = ExchangeRates.where("time > ? AND time < ?", er.time.beginning_of_day, er.time.end_of_day)

This will translate your request directly into the SQL. While it's much less ActiveRecord "ish" than I prefer, I've found no good way to do something simple that searches for ranges.

If you want something even cleaner you could consider monkey patching AR to support a range operation that effectively does something like this under the hood with the passed in hash.

Answer 2

This should work for you

per = ExchangeRates.where(time: er.time.beginning_of_day..er.time.end_of_day).first

However, when i frequently use this type of query on a model, i prefer to duplicate data, and also use a date column.

Lets say, if i have a created_at column, i also add a created_on column. One has datetime type, letter has date type.