Time Availability Comparison, Using Ruby on Rails

Time availability comparison, using Ruby on Rails

You don't need to have such a complex model. All you need is a table that shows the blocks of time for which the rental units are not available, in other words, a table with booked times for each rental unit. For example:

create table BOOKING 
( rental_unit_id  int 
, start_datetime  date
, end_datetime    date
)

Now if you want to get a list of rental units that are available for the entirety of a given time block, say @Arrive to @Depart then all you have to do is run a query like this:

select R.rental_unit_id -- (and anything else you want)
from RENTAL_UNIT R
where not exists ( select B.rental_unit_id
                   from BOOKING B
                   where B.rental_unit_id = R.rental_unit_id
                     and end_datetime > @Arrive
                     and start_datetime < @Depart )

This query says get me a list of rental units where there is no booking which overlaps the search period of interest (from @Arrive to @Depart). Note that you can play with <= @Depart depending on whether you want to have an inclusive or exclusive endpoint for your booking periods.

EDIT: Handling multiple availability blocks

@OP has added a requirement for multiple availability blocks. If you are renting equipment over multiple days then @Arrive and @Depart just happen on different dates. If, as in @OP's example, the multiple days have gaps in the middle - presumably where the equipment is returned and can be rented to someone else - then you just have to add extra where not exists clauses - one for each independent block of desired availability. Just "and" them together and you will find the rental units that are available in all of the desired time blocks. The notion of better or worse matches doesn't really apply. A rental unit is either available or it isn't.

Rails 3 - Time Comparison?

You want:

if record.updated_at < 15.minutes.ago

That's "less-than" as in "before".

Trouble comparing time with RSpec

Ruby Time object maintains greater precision than the database does. When the value is read back from the database, it’s only preserved to microsecond precision, while the in-memory representation is precise to nanoseconds.

If you don't care about millisecond difference, you could do a to_s/to_i on both sides of your expectation

expect(@article.updated_at.utc.to_s).to eq(Time.now.to_s)

or

expect(@article.updated_at.utc.to_i).to eq(Time.now.to_i)

Refer to this for more information about why the times are different

Compare date_time with today's date

Using Time.new("%Y-%m-%d") will produce an empty Time object:

Time.new("%Y-%m-%d")
# => 0000-01-01 00:00:00 +0730

What you want to do is compare to Time.now:

<% if Time.now < flight.flight_date %>

Or, if using Rails, you might want to use Time.current, or Date.current:

<% if Date.current < flight.flight_date %>

or

<% if Time.current < flight.flight_date %>

activerecord comparing times

@schedules = Schedule.where("team_id = ? and event = ? and time >= ?", [current_user[:team_id], "1", Time.zone.now])

The string is used directly in the SQL query so you need to make sure the column names are correct and unambiguous (if you joined on another table that also has a team_id colum, you would need to do schedules.team_id = ? and ...)

Comparing the DateTime Objects in Ruby on Rails

Answering this question is a bit tricky without knowing the type of @model_name.schedule_time.

However in rails ActiveSupport provides the methods #past? and #future? to Date, DateTime and Time instances, so that should take care of your problem:

Date.yesterday.past? => true
Time.now.end_of_day.future? => true
DateTime.now.beginning_of_day.past? => true

If @model_name.schedule_time does not respond to these methods, then it is not one of those types, which explains that the comparison you tried did not work.

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