# class ActiveRecord::Result

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

### Attributes

column_types[R]
columns[R]
rows[R]

### Public Class Methods

new(columns, rows, column_types = {}) click to toggle source

    # File lib/active_record/result.rb, line 37
    def initialize(columns, rows, column_types = {})
      @columns      = columns
      @rows         = rows
      @hash_rows    = nil
      @column_types = column_types
    end

### Public Instance Methods

[](idx) click to toggle source

    # File lib/active_record/result.rb, line 79
    def [](idx)
      hash_rows[idx]
    end

each() { |row| ... } click to toggle source

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

Returns an `Enumerator` if no block is given.

    # File lib/active_record/result.rb, line 53
    def each
      if block_given?
        hash_rows.each { |row| yield row }
      else
        hash_rows.to_enum { @rows.size }
      end
    end

empty?() click to toggle source

Returns true if there are no records, otherwise false.

    # File lib/active_record/result.rb, line 70
    def empty?
      rows.empty?
    end

first() click to toggle source

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

    # File lib/active_record/result.rb, line 85
    def first
      return nil if @rows.empty?
      Hash[@columns.zip(@rows.first)]
    end

initialize_copy(other) click to toggle source

    # File lib/active_record/result.rb, line 106
    def initialize_copy(other)
      @columns      = columns.dup
      @rows         = rows.dup
      @column_types = column_types.dup
      @hash_rows    = nil
    end

last() click to toggle source

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

    # File lib/active_record/result.rb, line 92
    def last
      return nil if @rows.empty?
      Hash[@columns.zip(@rows.last)]
    end

length() click to toggle source

Returns the number of elements in the rows array.

    # File lib/active_record/result.rb, line 45
    def length
      @rows.length
    end

to_ary() click to toggle source

Returns an array of hashes representing each row record.

    # File lib/active_record/result.rb, line 75
    def to_ary
      hash_rows
    end

to_hash() click to toggle source

Returns an array of hashes representing each row record.

    # File lib/active_record/result.rb, line 62
    def to_hash
      hash_rows
    end

### Private Instance Methods

column_type(name, type_overrides = {}) click to toggle source

    # File lib/active_record/result.rb, line 115
    def column_type(name, type_overrides = {})
      type_overrides.fetch(name) do
        column_types.fetch(name, Type.default_value)
      end
    end

hash_rows() click to toggle source

    # File lib/active_record/result.rb, line 121
    def hash_rows
      @hash_rows ||=
        begin
          # We freeze the strings to prevent them getting duped when
          # used as keys in ActiveRecord::Base's @attributes hash
          columns = @columns.map { |c| c.dup.freeze }
          @rows.map { |row|
            # In the past we used Hash[columns.zip(row)]
            #  though elegant, the verbose way is much more efficient
            #  both time and memory wise cause it avoids a big array allocation
            #  this method is called a lot and needs to be micro optimised
            hash = {}

            index = 0
            length = columns.length

            while index < length
              hash[columns[index]] = row[index]
              index += 1
            end

            hash
          }
        end
    end