/**
* Write all the changes we have recorded to the database.
* @param question_engine_data_mapper $dm the mapper to use to update the database.
*/
public function save(question_engine_data_mapper $dm)
{
$dm->delete_steps(array_keys($this->stepsdeleted), $this->quba->get_owning_context());
// Initially an array of array of question_attempt_step_objects.
// Built as a nested array for efficiency, then flattened.
$stepdata = array();
foreach ($this->stepsmodified as $stepinfo) {
list($step, $questionattemptid, $seq) = $stepinfo;
$stepdata[] = $dm->update_question_attempt_step($step, $questionattemptid, $seq, $this->quba->get_owning_context());
}
foreach ($this->stepsadded as $stepinfo) {
list($step, $questionattemptid, $seq) = $stepinfo;
$stepdata[] = $dm->insert_question_attempt_step($step, $questionattemptid, $seq, $this->quba->get_owning_context());
}
foreach ($this->attemptsmodified as $qa) {
$dm->update_question_attempt($qa);
}
foreach ($this->attemptsadded as $qa) {
$stepdata[] = $dm->insert_question_attempt($qa, $this->quba->get_owning_context());
}
foreach ($this->metadataadded as $info) {
$qa = reset($info);
$stepdata[] = $dm->insert_question_attempt_metadata($qa, array_keys($info));
}
foreach ($this->metadatamodified as $info) {
$qa = reset($info);
$stepdata[] = $dm->update_question_attempt_metadata($qa, array_keys($info));
}
if ($this->modified) {
$dm->update_questions_usage_by_activity($this->quba);
}
if ($stepdata) {
$dm->insert_all_step_data(call_user_func_array('array_merge', $stepdata));
}
$this->stepsdeleted = array();
$this->stepsmodified = array();
$this->stepsadded = array();
$this->attemptsdeleted = array();
$this->attemptsadded = array();
$this->attemptsmodified = array();
$this->modified = false;
}
