Schema for opening hours MongoDB - mongodb

Question

How would you store opening hours on a document, say a Library, in mongoDB, that's easily queryable with Mongoid? I've read this thread, but I'm not sure how it would be implemented with my needs.
I need to have the ability to add multiple opening and closing times per day since the Library should be able to close some hours during the day and then reopen.
I need to be able to add exceptions to these opening hours. For example; close monday on a specific date.
Please share some best practices and experiences on how one could do this the most flexible way.

Answer 1

Thank you, Yeggeps, for the list of requirements.
This is a revised answer based on your requirements. Of course there is no holy grail to schemae, but I would like to motivate my answer before revision (keeping a flat structure is easy to query and maintain) with some sample data + queries based on your requirement list. I reiterate, I am not saying this is the best solution, but it is a solution which is straightforward to query and easy to maintain (imho).
Code is a little quick and dirty, apologies. The data:
[
# library "lib1" open on wednesdays from 8:00 until 17:00
{"lib_id" => "lib1", "type" => "hours", "opening" => 800, "closing" => 1700, "day_of_week" => 3},
# library "lib1" open on wednesdays from 19:00 until 22:15
{"lib_id" => "lib1", "type" => "hours", "opening" => 1900, "closing" => 2215, "day_of_week" => 3},
{"lib_id" => "lib1", "type" => "hours", "opening" => 800, "closing" => 1700, "day_of_week" => 4},
{"lib_id" => "lib2", "type" => "hours", "opening" => 1100, "closing" => 1700, "day_of_week" => 3},
{"lib_id" => "lib2", "type" => "hours", "opening" => 1400, "closing" => 1700, "day_of_week" => 4},
{"lib_id" => "lib2", "type" => "hours", "opening" => 1900, "closing" => 2100, "day_of_week" => 4},
# library lib1 closed on wednesday december 7th 2011
{"lib_id" => "lib1", "type" => "closed_on", "reason" => "Rearranging the shelves", "closed_date" => Time.utc(2011, 12, 8)},
{"lib_id" => "lib2", "type" => "closed_on", "reason" => "We are closed for the holidays", "closed_date" => Time.utc(2011, 12, 7)}
].each do |schedule|
coll.save(schedule)
end
Show opening hours and exceptional dates separately:
# List all the library id's distinctly
coll.distinct("lib_id").each do |lib_id|
puts "\nLibrary #{lib_id} opening hours:\n--- "
# I need to be able to show the opening hours in correlation with the Library
# Find all the opening hour information for current library
coll.find({"lib_id" => lib_id, "type" => "hours"}).each do |schedule|
puts " #{Date::DAYNAMES[schedule["day_of_week"]]}s: #{schedule["opening"]} - #{schedule["closing"]}" if schedule["type"] == "hours"
end
# I need to show an indication if it's open or closed in correlation with the Library.
puts "This library will be closed on: "
# Find all the exceptions for current lib_id -- introduce a time-period restriction using Date.utc (...)
coll.find({"lib_id" => lib_id, "type" => "closed_on"}).each do |closed|
puts " #{closed["closed_date"].strftime("%a %B%e, %Y")}: #{closed["reason"]}"
end
end
Which libraries are open today?
# I need to be able to query on what's open right now or some time in the future with minute granularity
# here I'll also need to be able to exclude the Librarys that has added exceptions for the given time/day
puts "---"
qtime = (Time.now.hour * 100) + Time.now.min # minute granularity
qwday = Time.now.wday # this example only shows today
qclosed = Time.utc(Time.now.year, Time.now.mon, Time.now.mday)
# Query for all library ids which have opening times for this weekday, at this hour (+minutes)
coll.find({"opening" => {"$lte" => qtime}, "closing" => {"$gte" => qtime}, "day_of_week" => qwday}, {:fields => "lib_id"}).each do |lib|
# Check whether current library has an exception for this specific day
closed = coll.find_one({"lib_id" => lib["lib_id"], "closed_date" => qclosed})
if closed
# If an exception record was encountered, print the reason
puts "Library #{lib["lib_id"]} is normally open right now, but is now closed: '#{closed["reason"]}'"
else
# Else: the library is open
puts "Library #{lib["lib_id"]} is open right now! (#{Time.now.strftime("%a %B%e %Y, %H:%M")})"
end
end
Produces output as follows:
Library lib1 opening hours:
---
Wednesdays: 800 - 1700
Wednesdays: 1900 - 2215
Thursdays: 800 - 1700
This library will be closed on:
Thu December 8, 2011: Rearranging the shelves
Library lib2 opening hours:
---
Wednesdays: 1100 - 1700
Thursdays: 1400 - 1700
Thursdays: 1900 - 2100
This library will be closed on:
Wed December 7, 2011: We are closed for the holidays
---
Library lib1 is open right now! (Wed December 7 2011, 13:12)
Library lib2 is normally open right now, but is now closed: 'We are closed for the holidays'
Admittedly, the downside to my proposed solution is that it does not capture every requirement in one query.

Answer 2

It's difficult to provide a good solution without knowing the exact queries you'd like to run. For instance, if you're asking "what businesses are open now (5:32 PM, 5/11/2011)?" you'd want a different schema than if you were asking "when is business XYZ open next?"
In the first case, you'll want to be able to efficiently pose range queries on the current hour, minute, and day -- as well as negative queries on an exception list. Alternatively, you can handle exceptions in client code.
Last, what is the level of granularity needed? What is the smallest exception possible? Minutes? Hours? Days?
I'd post the above as a comment but I just created a user account. With additional information, I'll update this to provide an actual answer.