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Class: ActiveRecord::Result

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, ::Enumerable
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.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_hash
# => [{"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

Class Method Summary

Instance Attribute Summary

::Enumerable - Included

#many?

Returns true if the enumerable has more than 1 element.

Instance Method Summary

::Enumerable - Included

#exclude?

The negative of the Enumerable#include?.

#index_by

Convert an enumerable to a hash.

#pluck

Convert an enumerable to an array based on the given key.

#sum

Calculates a sum from the elements.

#without

Returns a copy of the enumerable without the specified elements.

Constructor Details

.new(columns, rows, column_types = {}) ⇒ Result

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 39

def initialize(columns, rows, column_types = {})
  @columns      = columns
  @rows         = rows
  @hash_rows    = nil
  @column_types = column_types
end

Instance Attribute Details

#column_types (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 37

attr_reader :columns, :rows, :column_types

#columns (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 37

attr_reader :columns, :rows, :column_types

#empty?Boolean (readonly)

Returns true if there are no records, otherwise false.

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 72

def empty?
  rows.empty?
end

#rows (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 37

attr_reader :columns, :rows, :column_types

Instance Method Details

#[](idx)

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 81

def [](idx)
  hash_rows[idx]
end

#collect!

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 69

alias :collect! :map

#each

Calls the given block once for each element in row collection, passing row as parameter.

Returns an Enumerator if no block is given.

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 55

def each
  if block_given?
    hash_rows.each { |row| yield row }
  else
    hash_rows.to_enum { @rows.size }
  end
end

#first

Returns the first record from the rows collection. If the rows collection is empty, returns nil.

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 87

def first
  return nil if @rows.empty?
  Hash[@columns.zip(@rows.first)]
end

#initialize_copy(other)

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 108

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

#last

Returns the last record from the rows collection. If the rows collection is empty, returns nil.

[ GitHub ]

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

def last
  return nil if @rows.empty?
  Hash[@columns.zip(@rows.last)]
end

#length

Returns the number of elements in the rows array.

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 47

def length
  @rows.length
end

#map!

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 68

alias :map! :map

#to_ary

Returns an array of hashes representing each row record.

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 77

def to_ary
  hash_rows
end

#to_hash

Returns an array of hashes representing each row record.

[ GitHub ]

  
# File 'activerecord/lib/active_record/result.rb', line 64

def to_hash
  hash_rows
end