Commits a transaction.

Remove entities in a transaction.

dataset.transaction do |tx|
  if tx.find(user.key).nil?
    tx.delete task1, task2
  end
end

Reset the transaction. #start must be called afterwards.

Rolls a transaction back.

Persist entities in a transaction.

dataset.transaction do |tx|
  if tx.find(user.key).nil?
    tx.save task1, task2
  end
end

Begins a transaction. This method is run when a new Transaction is created.