require "active_record"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Migration.class_eval do
  create_table(:records) do |t|
    t.string :column
  end
end

data = 50_000.times.map { |i| Hash[column: "Column #{i}"] }

# =============================================================

data.each do |hash|
 insert          = Arel::Nodes::InsertStatement.new
 insert.relation = Arel::Table.new(:records)
 insert.columns  = hash.keys.map { |k| Arel::Table.new(:records)[k] }
 insert.values   = Arel::Nodes::Values.new(hash.values, insert.columns)

 ActiveRecord::Base.connection.execute(insert.to_sql)
end

# Takes 20 seconds, because of 50,000 INSERT statements, since Arel doesn't support
# INSERTing multiple records in a single query. This code is obviously really ugly.