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Class: ActiveRecord::Result

Relationships & Source Files
Namespace Children
Classes:
IndexedRow
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, ::Enumerable, ::ActiveSupport::EnumerableCoreExt::Constants
Inherits: Object
Defined in: activerecord/lib/active_record/result.rb

Overview

This class encapsulates a result returned from calling #exec_query on any database connection adapter. For example:

result = ActiveRecord::Base.lease_connection.exec_query('SELECT id, title, body FROM posts')
result # => #<ActiveRecord::Result:0xdeadbeef>

# Get the column names of the result:
result.columns
# => ["id", "title", "body"]

# Get the record values of the result:
result.rows
# => [[1, "title_1", "body_1"],
      [2, "title_2", "body_2"],
      #...
     ]

# Get an array of hashes representing the result (column => value):
result.to_a
# => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
      {"id" => 2, "title" => "title_2", "body" => "body_2"},
      #...
     ]

# ActiveRecord::Result also includes Enumerable.
result.each do |row|
  puts row['title'] + " " + row['body']
end

Constant Summary

Class Method Summary

Instance Attribute Summary

::Enumerable - Included

#many?

Returns true if the enumerable has more than 1 element.

Instance Method Summary

::Enumerable - Included

#compact_blank

Returns a new ::Array without the blank items.
#exclude?

The negative of the Enumerable#include?.
#excluding

Returns a copy of the enumerable excluding the specified elements.
#in_order_of

Returns a new ::Array where the order has been set to that provided in the series, based on the key of the objects in the original enumerable.
#including

Returns a new array that includes the passed elements.
#index_by

Convert an enumerable to a hash, using the block result as the key and the element as the value.
#index_with

Convert an enumerable to a hash, using the element as the key and the block result as the value.
#maximum

Calculates the maximum from the extracted elements.
#minimum

Calculates the minimum from the extracted elements.
#pick

Extract the given key from the first element in the enumerable.
#pluck

Extract the given key from each element in the enumerable.
#sole

Returns the sole item in the enumerable.
#without

Alias for Enumerable#excluding.
#as_json

::ActiveSupport::EnumerableCoreExt::Constants - Included

#const_missing

Constructor Details

.new(columns, rows, column_types = nil) ⇒ Result

[ GitHub ] 

  


# File 'activerecord/lib/active_record/result.rb', line 102



def initialize(columns, rows, column_types = nil)
  # We freeze the strings to prevent them getting duped when
  # used as keys in ActiveRecord::Base's @attributes hash
  @columns      = columns.each(&:-@).freeze
  @rows         = rows
  @hash_rows    = nil
  @column_types = column_types.freeze
  @types_hash   = nil
  @column_indexes = nil
end


  







Class Method Details



  

    .empty(async: false)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 94



def self.empty(async: false) # :nodoc:
  if async
    EMPTY_ASYNC
  else
    EMPTY
  end
end


  







Instance Attribute Details



  

    #columns   (readonly)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 92



attr_reader :columns, :rows


  








  

    #empty?  ⇒ Boolean  (readonly)
  



  

    

Returns true if there are no records, otherwise false.


  





  


  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 138



def empty?
  rows.empty?
end


  








  

    #rows   (readonly)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 92



attr_reader :columns, :rows


  







Instance Method Details



  

    #[](idx)  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 149



def [](idx)
  hash_rows[idx]
end


  








  

    #cancel  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 180



def cancel # :nodoc:
  self
end


  








  

    #cast_values(type_overrides = nil)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 184



def cast_values(type_overrides = nil) # :nodoc:
  if columns.one?
    # Separated to avoid allocating an array per row

    type = if type_overrides.is_a?(Array)
      type_overrides.first
    else
      column_type(columns.first, 0, type_overrides)
    end

    rows.map do |(value)|
      type.deserialize(value)
    end
  else
    types = if type_overrides.is_a?(Array)
      type_overrides
    else
      columns.map.with_index { |name, i| column_type(name, i, type_overrides) }
    end

    rows.map do |values|
      Array.new(values.size) { |i| types[i].deserialize(values[i]) }
    end
  end
end


  








  

    #column_indexes  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 222



def column_indexes # :nodoc:
  @column_indexes ||= begin
    index = 0
    hash = {}
    length = columns.length
    while index < length
      hash[columns[index]] = index
      index += 1
    end
    hash.freeze
  end
end


  








  

    #column_type(name, index, type_overrides)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 243



def column_type(name, index, type_overrides)
  if type_overrides
    type_overrides.fetch(name) do
      column_type(name, index, nil)
    end
  elsif @column_types
    @column_types[index] || Type.default_value
  else
    Type.default_value
  end
end


  








  

    #column_types  
  



  

    

Returns the Type type of all columns. Note that not all database adapters return the result types, so the hash may be empty.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 161



def column_types
  if @column_types
    @types_hash ||= begin
      types = {}
      @columns.each_with_index do |name, index|
        type = @column_types[index] || Type.default_value
        types[name] = types[index] = type
      end
      types.freeze
    end
  else
    EMPTY_HASH
  end
end


  








  

    #each(&block)  
  



  

    

Calls the given block once for each element in row collection, passing row as parameter. Each row is a Hash-like, read only object.



To get real hashes, use .to_a.each.



Returns an Enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 129



def each(&block)
  if block_given?
    hash_rows.each(&block)
  else
    hash_rows.to_enum { @rows.size }
  end
end


  








  

    #freeze  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 215



def freeze # :nodoc:
  hash_rows.freeze
  indexed_rows
  column_types
  super
end


  








  

    #hash_rows   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 255



def hash_rows
  # We use transform_values to rows.
  # This is faster because we avoid any reallocs and avoid hashing entirely.
  @hash_rows ||= @rows.map do |row|
    column_indexes.transform_values { |index| row[index] }
  end
end


  








  

    #includes_column?(name)  ⇒ Boolean 
  



  

    

Returns true if this result set includes the column named name


  





  


  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 114



def includes_column?(name)
  @columns.include? name
end


  








  

    #indexed_rows  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 235



def indexed_rows # :nodoc:
  @indexed_rows ||= begin
    columns = column_indexes
    @rows.map { |row| IndexedRow.new(columns, row) }.freeze
  end
end


  








  

    #initialize_copy(other)  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 210



def initialize_copy(other)
  @rows = rows.dup
  @hash_rows    = nil
end


  








  

    #last(n = nil)  
  



  

    

Returns the last record from the rows collection.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 154



def last(n = nil)
  n ? hash_rows.last(n) : hash_rows.last
end


  








  

    #length  
  



  

    

Returns the number of elements in the rows array.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 119



def length
  @rows.length
end


  








  

    #result  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 176



def result # :nodoc:
  self
end


  








  

    #to_a  
  



  

    

Alias for #to_ary.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 147



alias :to_a :to_ary


  








  

    #to_ary  
    Also known as: #to_a
  



  

    

Returns an array of hashes representing each row record.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/result.rb', line 143



def to_ary
  hash_rows
end