问题
I am working on a Rails project using a Postgres database. For one of my models, I have a time column, called (cleverly) time. When I created the model, I set the data type for this column as 'time', with the (perhaps incorrect) understanding that this data type was for storing time only, no date.
t.time :time
However, when I submit data to the model, the time is correct but prefixed by an incorrect date:
time: "2000-01-01 16:57:19"
I just want the column to store the time (like '16:57:19'). Is 'time' the correct data type to use? Or is there some other way I should handle this problem?
Thank you very much.
回答1:
The problem is that there is no time-of-day class in Ruby or Rails. All the time classes are dates or timestamps (i.e. date plus time of day).
Inside the database it will be a time (without timezone) column and it will behave properly inside the database. However, once the time gets into Ruby, ActiveRecord will add a date component because there is no plain time-of-day class available, it just happens to use 2000-01-01 as the date.
Everything will be fine inside the database but you'll have to exercise a little bit of caution to ignore the date component when you're outside the database in Rails.
来源：https://stackoverflow.com/questions/34978905/rails-activerecord-postgres-time-format