activerecord - How to reduce number of queries in this case on Rails -

activerecord - How to reduce number of queries in this case on Rails -

i need bunch of queries.

in case think query result many times,

not completed in 1 query.

how create search results can done 1 query ?

q = weatherlog.nearby(100, longitude, latitude) if start_time , end_time @weather_logs = q.where(datetime: start_time..end_time) elsif start_time @weather_logs = q.where("datetime > ?", start_time) elsif end_time @weather_logs = q.where("datetime < ?", end_time) end @weather_logs = @weather_logs.order(datetime: :asc).first(2000)

the first thing realize activerecord not execute query until aboultely has (lazy loading). while there number of lines of code building query, query executed on methods .all, .each, .first etc. performance standpoint code ok executing 1 query database , not many.

however can tweak code create more human readable , maintainable:

class weatherlog < activerecord::base # ... class << self def between_times(times) after_time(times[:start_time]).before_time(times[:end_time]) end def after_time(time) homecoming self.all if time.nil? where('datetime > ?', time) end def before_time(time) homecoming self.all if time.nil? where('datetime < ?', time) end end end

using self.all skips query status while still enabling query chaining. makes possible remove of if/else logic. can chain queries (or create helper method within weatherlog):

weatherlog.nearby(100, longitude, latitude).between_times(start_time: start_time, end_time: end_time)

ruby-on-rails activerecord ruby-on-rails-4