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_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
Attributes
column_types[R]
columns[R]
rows[R]
Public Class Methods
new(columns, rows, column_types = {})
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# File 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
Public Instance Methods
[](idx)
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# File lib/active_record/result.rb, line 85 def [](idx) hash_rows[idx] end
each() { |row| ... }
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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 60 def each if block_given? hash_rows.each { |row| yield row } else hash_rows.to_enum { @rows.size } end end
empty?()
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Returns true if there are no records, otherwise false.
# File lib/active_record/result.rb, line 74 def empty? rows.empty? end
includes_column?(name)
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Returns true if this result set includes the column named name
# File lib/active_record/result.rb, line 47 def includes_column?(name) @columns.include? name end
initialize_copy(other)
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# File lib/active_record/result.rb, line 120 def initialize_copy(other) @columns = columns.dup @rows = rows.dup @column_types = column_types.dup @hash_rows = nil end
last(n = nil)
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Returns the last record from the rows collection.
# File lib/active_record/result.rb, line 90 def last(n = nil) n ? hash_rows.last(n) : hash_rows.last end
length()
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Returns the number of elements in the rows array.
# File lib/active_record/result.rb, line 52 def length @rows.length end
to_ary()
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Returns an array of hashes representing each row record.
# File lib/active_record/result.rb, line 79 def to_ary hash_rows end
Also aliased as: to_a
Private Instance Methods
column_type(name, type_overrides = {})
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# File lib/active_record/result.rb, line 128 def column_type(name, type_overrides = {}) type_overrides.fetch(name) do column_types.fetch(name, Type.default_value) end end
hash_rows()
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# File lib/active_record/result.rb, line 134 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(&:-@) length = columns.length template = nil @rows.map { |row| if template # We use transform_values to build subsequent rows from the # hash of the first row. This is faster because we avoid any # reallocs and in Ruby 2.7+ avoid hashing entirely. index = -1 template.transform_values do row[index += 1] end else # 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 while index < length hash[columns[index]] = row[index] index += 1 end # It's possible to select the same column twice, in which case # we can't use a template template = hash if hash.length == length hash end } end end