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Module: Mongoid::Contextual::Aggregable::Mongo

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Included In:
::Mongoid::Contextual::Mongo
Defined in: lib/mongoid/contextual/aggregable/mongo.rb

Overview

Contains behavior for aggregating values in Mongo.

Instance Method Summary

Instance Method Details

#aggregates(field) ⇒ Hash

Get all the aggregate values for the provided field.

Examples:

Get all the aggregate values.

aggregable.aggregates(:likes)
# => {
#   "count" => 2.0,
#   "max" => 1000.0,
#   "min" => 500.0,
#   "sum" => 1500.0,
#   "avg" => 750.0
# }

Parameters:

Returns:

  • (Hash) —

    A Hash containing the aggregate values. If no documents are found, then returned ::Hash will have count, sum of 0 and max, min, avg of nil.

[ GitHub ] 

  


# File 'lib/mongoid/contextual/aggregable/mongo.rb', line 29



def aggregates(field)
  result = collection.aggregate(pipeline(field), session: _session).to_a
  if result.empty?
    Aggregable::EMPTY_RESULT.dup
  else
    result.first
  end
end


  








  

    #avg(field)  ⇒ Float 
  



  

    

Get the average value of the provided field.


  





    

    
Examples:

        


Get the average of a single field.



      
aggregable.avg(:likes)

  


Parameters:


    
  
  • 
    field
    (Symbol)
—    
    

    The field to average.
    

    
  
    • 



Returns:


    
  
  • 
    (Float)
—    
    

    The average.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongoid/contextual/aggregable/mongo.rb', line 46



def avg(field)
  aggregates(field)["avg"]
end


  








  

    #max(field = nil)  ⇒ Float | Document 
  



  

    

Get the max value of the provided field. If provided a block, will return the ::Mongoid::Document with the greatest value for the field, in accordance with Ruby’s enumerable API.


  





    

    
Examples:

        


Get the max of a single field.



      
aggregable.max(:likes)

        


Get the document with the max value.



      
aggregable.max do |a, b|
  a.likes <=> b.likes
end

  


Parameters:


    
  
  • 
    field
    (Symbol)
    (defaults to: nil)
—    
    

    The field to max.
    

    
  
    • 



Returns:


    
  
  • 
    (Float | Document)
—    
    

    The max value or document with the max value.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongoid/contextual/aggregable/mongo.rb', line 66



def max(field = nil)
  block_given? ? super() : aggregates(field)["max"]
end


  








  

    #min(field = nil)  ⇒ Float | Document 
  



  

    

Get the min value of the provided field. If provided a block, will return the ::Mongoid::Document with the smallest value for the field, in accordance with Ruby’s enumerable API.


  





    

    
Examples:

        


Get the min of a single field.



      
aggregable.min(:likes)

        


Get the document with the min value.



      
aggregable.min do |a, b|
  a.likes <=> b.likes
end

  


Parameters:


    
  
  • 
    field
    (Symbol)
    (defaults to: nil)
—    
    

    The field to min.
    

    
  
    • 



Returns:


    
  
  • 
    (Float | Document)
—    
    

    The min value or document with the min value.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongoid/contextual/aggregable/mongo.rb', line 86



def min(field = nil)
  block_given? ? super() : aggregates(field)["min"]
end


  








  

    #pipeline(field)  ⇒ Array  (private)
  

  

    This method is for internal use only.
  



  

    

Get the aggregation pipeline for provided field.


  





    

    
Examples:

        


Get the pipeline.



      
aggregable.pipeline(:likes)

  


Parameters:



Returns:


    
  
  • 
    (Array)
—    
    

    The array of pipeline operators.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongoid/contextual/aggregable/mongo.rb', line 118



def pipeline(field)
  db_field = "$#{database_field_name(field)}"
  sort, skip, limit = criteria.options.values_at(:sort, :skip, :limit)

  pipeline = []
  pipeline << { "$match" =>  criteria.exists(field => true).selector }
  pipeline << { "$sort" => sort } if sort && (skip || limit)
  pipeline << { "$skip" => skip } if skip
  pipeline << { "$limit" => limit } if limit
  pipeline << {
    "$group"  => {
      "_id"   => field.to_s,
      "count" => { "$sum" => 1 },
      "max"   => { "$max" => db_field },
      "min"   => { "$min" => db_field },
      "sum"   => { "$sum" => db_field },
      "avg"   => { "$avg" => db_field }
    }
  }
end


  








  

    #sum(field = nil)  ⇒ Float 
  



  

    

Get the sum value of the provided field. If provided a block, will return the sum in accordance with Ruby’s enumerable API.


  





    

    
Examples:

        


Get the sum of a single field.



      
aggregable.sum(:likes)

        


Get the sum for the provided block.



      
aggregable.sum(&:likes)

  


Parameters:


    
  
  • 
    field
    (Symbol)
    (defaults to: nil)
—    
    

    The field to sum.
    

    
  
    • 



Returns:


    
  
  • 
    (Float)
—    
    

    The sum value.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongoid/contextual/aggregable/mongo.rb', line 102



def sum(field = nil)
  block_given? ? super() : aggregates(field)["sum"] || 0
end