/**
* This function will delete numerous tag instances efficiently.
* This removes tag instances only. It doesn't check to see if it is the last use of a tag.
*
* @param array $instances An array of tag instance objects with the addition of the tagname and tagrawname
* (used for recording a delete event).
*/
function tag_bulk_delete_instances($instances)
{
global $DB;
$instanceids = array();
foreach ($instances as $instance) {
$instanceids[] = $instance->id;
}
// This is a multi db compatible method of creating the correct sql when using the 'IN' value.
// $insql is the sql statement, $params are the id numbers.
list($insql, $params) = $DB->get_in_or_equal($instanceids);
$sql = 'id ' . $insql;
$DB->delete_records_select('tag_instance', $sql, $params);
// Now go through and record each tag individually with the event system.
foreach ($instances as $instance) {
// Trigger tag removed event (i.e. The tag instance has been removed).
$event = \core\event\tag_removed::create(array('objectid' => $instance->id, 'contextid' => $instance->contextid, 'other' => array('tagid' => $instance->tagid, 'tagname' => $instance->name, 'tagrawname' => $instance->rawname, 'itemid' => $instance->itemid, 'itemtype' => $instance->itemtype)));
unset($instance->name);
unset($instance->rawname);
$event->add_record_snapshot('tag_instance', $instance);
$event->trigger();
}
}
/**
* Delete one instance of a tag. If the last instance was deleted, it will also delete the tag, unless its type is 'official'.
*
* @package core_tag
* @category tag
* @access public
* @param string $record_type the type of the record for which to remove the instance
* @param int $record_id the id of the record for which to remove the instance
* @param int $tagid the tagid that needs to be removed
* @param int $userid (optional) the userid
* @return bool true on success, false otherwise
*/
function tag_delete_instance($record_type, $record_id, $tagid, $userid = null)
{
global $DB;
if (is_null($userid)) {
$taginstance = $DB->get_record('tag_instance', array('tagid' => $tagid, 'itemtype' => $record_type, 'itemid' => $record_id));
} else {
$taginstance = $DB->get_record('tag_instance', array('tagid' => $tagid, 'itemtype' => $record_type, 'itemid' => $record_id, 'tiuserid' => $userid));
}
if ($taginstance) {
// Get the tag.
$tag = $DB->get_record('tag', array('id' => $tagid));
$DB->delete_records('tag_instance', array('id' => $taginstance->id));
// We can not fire an event with 'null' as the contextid.
if (is_null($taginstance->contextid)) {
$taginstance->contextid = context_system::instance()->id;
}
// Trigger tag removed event.
$event = \core\event\tag_removed::create(array('objectid' => $taginstance->id, 'contextid' => $taginstance->contextid, 'other' => array('tagid' => $tag->id, 'tagname' => $tag->name, 'tagrawname' => $tag->rawname, 'itemid' => $taginstance->itemid, 'itemtype' => $taginstance->itemtype)));
$event->add_record_snapshot('tag_instance', $taginstance);
$event->trigger();
// If there are no other instances of the tag then consider deleting the tag as well.
if (!$DB->record_exists('tag_instance', array('tagid' => $tagid))) {
// If the tag is a personal tag then delete it - don't delete official tags.
if ($tag->tagtype == 'default') {
tag_delete($tagid);
}
}
} else {
return false;
}
return true;
}
