I'm scoping out how to handle user-generated dates with rails and was hoping to get some thoughts on the best way to handle them. Ultimately I want to display dates/times provided by the user in HTML, and I also want to sort by the dates (ascending and descending, depending). My initial thought was to create the db as time: string and date:string and then convert these strings to datetime values. Is there a better way to go about this? I'm using RoR 3.1.
Any thoughts and ideas would be greatly appreciated so I don't start down the wrong path only to realize at a later date.
Yes, there is a better way to go about it. ActiveRecord supports the following types for times:
datetime
timestamp
time
date
So pick the type that matches your intent (time for time of day, date for a date, ...) and then let AR do its job and deal with the details. Then you'll get the right data in the database and the right objects in your Ruby; once you have the right objects in your Ruby everything will sort and compare and what not properly.
Related
I want to allow teachers to be able to login to my Rails 3.2 app and be able to set when they are available. So instead of having two datetime fields where an actual date is stored is stored for starts_at and ends_at, I'd like for them just to say I'm available on "Mondays between 4:00pm and 5:00pm" with all three values being dropdowns.
The orignal way I approached this was having a string for day and using the time_select method in my form for my starts_at and ends_at. Unfortunately, time_select still comes with the date.
I'm just looking for the cleanest way to allow weekly scheduling. Is this possible? If it is, is there an easier way to do this? Thanks in advance for your tips.
take a look at
https://github.com/mzararagoza/rails-fullcalendar-icecube
its a small appointment app that i think that you can take allot out of it.
I have to store recurring date periods, similar to the one in the title, and I have no idea if there is an optimal day to do this. The first solution I came up with was to have day and month fields for start and end dates, but this solution doesnt sound very right to me.
I am using Ruby on Rails with SQL.
To store recurring dates of arbitrary complexity, you want to look into temporal expressions.
Some gems available are: runt, TExp or icecube
I've used both runt and icecube, as well as storing recurring dates (weekly schedules) in serialized ruby objects. The gems are the most flexible, if a little hard to use when your use case is simple.
Also if you need to parse textual expersions, look at Chronic
In ruby, you could probably express this nicely (for a particular year) with a Range:
(Time.utc(2012, 1, 1)..Time.utc(2012, 5, 1).end_of_month)
But storing this in a database...can only think of doing what you said (columns for start/end day and month), and then adding wrapper methods on the model similar to this:
def current_start
Time.utc(current_year, start_month, start_day)
end
...
def current_range
(current_start..current_end)
end
I would just use two dates... afaik that maps nicely to ruby Date objects anyway, with which you can do the usual arithmetic.
How do you compare dates with lua? What is the best string format for dates? Should I store dates in epoch? I am looking for performance ...
Is the best way os.difftime?
You are asking several things, so here are my answers:
Should I store dates in epoch?
In general yes, the best way to store the dates is by using epochs, as returned by os.time
How do you compare dates with lua?
It depends on how you want to "compare" them.
If you just want to know which one is newer/older, then the easiest fastest thing is storing them as "epochs" and then doing date1 < date2; since both dates are just numbers, this is both performant and clean.
If you want to know how many months/days/years have passed between two given dates, that's a bit more complex. You will need a code similar to this:
diff = os.date("*t", os.difftime(date1, date2))
On that example, the returned diff is a table similar to {year=1, month=5, day=1, hour=2, min=3, sec=40 ...}
I am looking for performance ...
If you are using os.date() too often to transform epochs into dates (for example, for printing) then you might want to "cache" the year, month, etc information in a table, so you don't have to call it again and again. But do this only if you experience a bad performance; don't pre-optimize.
What is the best string format for dates?
That completely depends on how you want to use them. For example, if your app interacts with another service that expects a certain date format, it makes sense to use that format in all your app.
If you have no particular need to use a format, then one candidate is (%x):
os.date("%x", date) -- 09/16/1998 (for example)
The string that gives you depends on the computer's locale. This might or might not be desirable.
If you want the representation to be the same across all computers, independently of their locale, you might want to try a standard format, like ISO 8601:
os.date("%Y-%m-%d", date) -- returns "1998-09-16" in all computers
This format has lots of advantages; the most obvious one is that dates sorted out alphabetically are also sorted out chronologically. But the most important one is that a lot of software out there is prepared to read/use it.
You can find more information about dates in Programming in Lua, Section 22.1 - Date and Time and in the lua-users wiki.
I have a Practice model that is storing start_time, end_time and day.
That information (like the rest of the site) will need to be displayed in 3 different
languages.
Start_time and end_time are both stored as Datetime types in the DB.
Day is not yet implemented, but will be shown as a select box. I have see people suggest an array of constants and storing it as an integer in the DB. While that seems reasonable, I am having trouble imagining that working well with different languages (using either I18n or Globalize2).
What is the cleanest way to implement this so it works well in different languages?
I can't see a good reason to store the days of the week in the database; I'd be surprised if such names will change and we are talking about 7 * 3 strings, that is a small amount of data to handle for your application.
i18n is the way to go. You can browser this repository to find day_names already traslated in different languages.
If you can't store or calculate the day of the week from the start and end DateTime objects, then I would recommend using an ENUM in the database - this causes the data to be stored as an integer - which takes up less space and is easier to index, and the conversion to the string types is done automatically for you so that you can query and insert strings, but the actual database values are integers.
Definitely do not store these values as strings though, it's harder to deal with them and they take up more space.
My database has a datetime field, and I want to be able to create new entries. Obviously the Rails datetime_select helper isn't the most user friendly thing to have in your form.
I'd rather have a text field for the datetime (or one for the date, and one for the time) and interpret the inputs like PHP strtotime can.
I might just be searching the wrong keywords. Surely this has been discussed in great depth somewhere.
Thanks
:0)
Check out Railscast #32, I've used this method a few times and it works pretty well.