Simple SQL bulk insert in Rails

bulk_insert.rb

# Takes a table name, and an array of hashes where keys are column names and values are values.
# Expects hashes to all contain the same keys.
def bulk_insert(table, rows)
  columns = rows.first.keys

  to_insert = rows.map do |d|
    vals = columns.map {|k| d[k] }
    ActiveRecord::Base.send(:replace_bind_variables, "(#{vals.length.times.collect {'?'}.join(',')})", vals)
  end

  ActiveRecord::Base.connection.execute(<<-SQL)
    INSERT INTO
      #{table}
    (#{columns.join(',')})
    VALUES #{to_insert.join(",")}
  SQL
end