Using a duration field in a Rails model
duration, ruby, ruby-on-rails, time
Solution
- Store as integers in your database (number of seconds, probably).
- Your entry form will depend on the exact use case. Dropdowns are painful; better to use small text fields for duration in hours + minutes + seconds.
- Simply run a `SUM` query over the duration column to produce a grand total. If you use integers, this is easy and fast.
Additionally:
- Use a helper to display the duration in your views. You can easily convert a duration as integer of seconds to `ActiveSupport::Duration` by using `123.seconds` (replace `123` with the integer from the database). Use `inspect` on the resulting `Duration` for nice formatting. (It is not perfect. You may want to write something yourself.)
- In your model, you'll probably want attribute readers and writers that return/take `ActiveSupport::Duration` objects, rather than integers. Simply define `duration=(new_duration)` and `duration`, which internally call `read_attribute` / `write_attribute` with integer arguments.
Problem
I'm looking for the best way to use a duration field in a Rails model. I would like the format to be HH:MM:SS (ex: 01:30:23). The database in use is sqlite locally and Postgres in production. I would also like to work with this field so I can take a look at all of the objects in the field and come up with the total time of all objects in that model and end up with something like: 30 records totaling 45 hours, 25 minutes, and 34 seconds. So what would work best for? - Field type for the migration - Form field for the CRUD forms (hour, minute, second drop downs?) - Least expensive method to generate the total duration of all records in the model