Hi,
I am doing an ActiveRecord find against the database, bringing back a
number of objects that have a created_on date between two dates.
After this fetch, I want to check if the result contains an object with
a specific date (actually I want to iterate through all days in a range,
and if the result contains a record, I want to get that record out of
the result array and interrogate it).
I know how to do this by doing a new ActiveRecord find for each date in
my iteration range, but I don''t want to do that as the overhead of so
many calls is too high. ]
So I need to keep my one hit on the database, but then query the result,
something like:
all_results = Item.where(--- created in my date range ---)
(start_date..end_date).each do |current_date|
if all_results.contains(:created_on => current_date)
... do something
else
do something else
end
end
My ActiveRecord is very poor - created_on is a field on the Item model,
but I can''t find out how to efficiently query an ActiveRecord result in
this way.
Any help much appreciated!
Thanks.
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On 16 December 2010 11:46, Peter Laurens <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Hi, > > I am doing an ActiveRecord find against the database, bringing back a > number of objects that have a created_on date between two dates. > > After this fetch, I want to check if the result contains an object with > a specific date (actually I want to iterate through all days in a range, > and if the result contains a record, I want to get that record out of > the result array and interrogate it). > > I know how to do this by doing a new ActiveRecord find for each date in > my iteration range, but I don''t want to do that as the overhead of so > many calls is too high. ] > > So I need to keep my one hit on the database, but then query the result, > something like: > > all_results = Item.where(--- created in my date range ---) > (start_date..end_date).each do |current_date| > if all_results.contains(:created_on => current_date) > ... do something > else > do something else > end > endI don''t understand, why not just use start_date and end_date as the range for your Item.where( ) call, then all the items returned will have been created in that range, do you can iterate through them all and do your ''...do something'' action Colin -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
My approach is this way because I can''t guarantee that there will be a record with a certain date, yet I want to produce an array of results for a full contiguous range of dates. In the case that there isn''t a record with a certain date, I still want to put in a ''placeholder value'' for that date in the array I''m creating. -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On 16 December 2010 12:09, Peter Laurens <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: Please quote the previous message so individual messages in the thread make sense.> My approach is this way because I can''t guarantee that there will be a > record with a certain date, yet I want to produce an array of results > for a full contiguous range of dates. In the case that there isn''t a > record with a certain date, I still want to put in a ''placeholder value'' > for that date in the array I''m creating.OK, I misunderstood. Going back to your original question then, you say:> I know how to do this by doing a new ActiveRecord find for each date in > my iteration range, but I don''t want to do that as the overhead of so > many calls is too high.How do you know that the overhead is too high? Colin -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
> Please quote the previous message so individual messages in the thread > make sense.Sure, sorry.> >> My approach is this way because I can''t guarantee that there will be a >> record with a certain date, yet I want to produce an array of results >> for a full contiguous range of dates. In the case that there isn''t a >> record with a certain date, I still want to put in a ''placeholder value'' >> for that date in the array I''m creating. > > OK, I misunderstood. Going back to your original question then, you > say: >> I know how to do this by doing a new ActiveRecord find for each date in >> my iteration range, but I don''t want to do that as the overhead of so >> many calls is too high. > > How do you know that the overhead is too high?I''ve tried this approach, where I request each date in a range individually, iterating over the range of dates I require. But the dates may span 30-60 days or even more, and this causes ~60 separate sql requests on the database. The result is a noticeable pause when loading the page (backed up by benchmark figures), and a solution which doesn''t scale to larger ranges of dates. -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On 16 December 2010 11:46, Peter Laurens <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Hi, > > I am doing an ActiveRecord find against the database, bringing back a > number of objects that have a created_on date between two dates. > > After this fetch, I want to check if the result contains an object with > a specific dateYou could use Enumerable::group_by to collect-up your records by date, and see if the resultant collection includes the date in question (and if not, add it if you need to) all_results = Item.where(--- created in my date range ---) grouped_all_results = all_results.group_by{|result| result.created_at.strftime("%Y%d%m")} if grouped_all_results.include?(current_time.strftime("%Y%d%m")) ... do something else do something else end You might make your group_by date and your lookup date by some other method (like "date_value.to_s" or something), but as long as they end up in the right format, it should work... -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On 16 December 2010 13:16, Michael Pavling <pavling-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> On 16 December 2010 11:46, Peter Laurens <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: >> Hi, >> >> I am doing an ActiveRecord find against the database, bringing back a >> number of objects that have a created_on date between two dates. >> >> After this fetch, I want to check if the result contains an object with >> a specific date > > You could use Enumerable::group_by to collect-up your records by date, > and see if the resultant collection includes the date in question (and > if not, add it if you need to)oh... or if you want it even simpler, just can use Enumerable.detect to find out yes/no on whether the collection contains any values with that date: all_results = Item.where(--- created in my date range ---) date_in_range = !!all_results.detect{|result| result.created_at.strftime("%Y%d%m")} or Array.select to return all the matches.... Basically, the Array and Enumerable APIs will probably have something for you - have a read ;-) http://ruby-doc.org/core/classes/Array.html http://ruby-doc.org/core/classes/Enumerable.html -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
> or Array.select to return all the matches.... > Basically, the Array and Enumerable APIs will probably have something > for you - have a read ;-) > > http://ruby-doc.org/core/classes/Array.html > http://ruby-doc.org/core/classes/Enumerable.htmlI think Array.select is the one for me, thanks! -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.