/**
* This will add a groupid to each of the submissions coming out of the moduleunion. This means getting
* all the group memberships for this course and choosing the maximum groupid. We can't count more than
* once when students are in two groups, so we need to do it like this. It's a greatest-n-per-group
* problem, solved with the classic left-join approach.
*
* @param block_ajax_marking_query $query
* @return void
*/
protected function alter_query(block_ajax_marking_query $query)
{
list($maxquery, $maxparams) = block_ajax_marking_group_max_subquery();
list($memberquery, $memberparams) = block_ajax_marking_group_members_subquery();
list($visibilitysubquery, $visibilityparams) = block_ajax_marking_group_visibility_subquery();
// We need to join to groups members to see if there are any memberships at all (in which case
// we use the highest visible id if there is one), or 0 if there are no memberships at all.
$table = array('join' => 'LEFT JOIN', 'table' => $memberquery, 'on' => 'membergroupquery.userid = moduleunion.userid
AND membergroupquery.coursemoduleid = moduleunion.coursemoduleid', 'alias' => 'membergroupquery', 'subquery' => true);
$query->add_from($table);
$query->add_params($memberparams);
// To make sure it's the highest visible one, we use this subquery as a greatest-n-per-group thing.
$table = array('join' => 'LEFT JOIN', 'table' => $maxquery, 'on' => 'membergroupquery.userid = maxgroupquery.userid
AND membergroupquery.coursemoduleid = maxgroupquery.coursemoduleid
AND maxgroupquery.groupid > membergroupquery.groupid', 'alias' => 'maxgroupquery', 'subquery' => true);
$query->add_from($table);
$query->add_params($maxparams);
// We join only if the group id is larger, then specify that it must be null. This means that
// the membergroupquery group id will be the largest available.
$query->add_where(array('type' => 'AND', 'condition' => 'maxgroupquery.groupid IS NULL'));
// Make sure it's not hidden. We want to know if there are people with no group, compared to a group that
// is hidden, so the aim is to get a null group id if there are no memberships by left joining, then
// hide that null row if the settings for group id 0 say so.
$table = array('join' => 'LEFT JOIN', 'table' => $visibilitysubquery, 'on' => '(membervisibilityquery.groupid = membergroupquery.groupid OR
(membervisibilityquery.groupid = 0 AND membergroupquery.groupid IS NULL))
AND membervisibilityquery.coursemoduleid = membergroupquery.coursemoduleid', 'alias' => 'membervisibilityquery', 'subquery' => true);
$query->add_from($table);
$query->add_params($visibilityparams);
$query->add_where(array('type' => 'AND', 'condition' => 'membervisibilityquery.coursemoduleid IS NULL'));
}
/**
* Needs to make sure that we get only the groups that are visible.
*
* Needs groups, coursemodules, a course and some settings.
*
* @todo Make this.
*/
public function test_group_max_subquery()
{
global $USER, $DB;
// Make a coursemodule, group, etc.
$this->set_up_for_group_subqueries();
// Get the query.
list($query, $params) = block_ajax_marking_group_max_subquery();
// Ought to be all groupid-userid-coursemoduleid triples for all group memberships.
// User1 is in group1 and there are two coursemodules. Should be 2 entries.
$results = $this->get_visibility_array_results($query, $params);
$this->assertEquals(2, count($results));
// TODO is it the right group?
// Hide one coursemodule and we ought to get one.
// Hide a group2a at coursemoduleid level.
$cmsetting = new stdClass();
$cmsetting->userid = $USER->id;
$cmsetting->tablename = 'course_modules';
$cmsetting->instanceid = $this->assign1->cmid;
$cmsetting->display = 1;
$cmsetting->id = $DB->insert_record('block_ajax_marking', $cmsetting);
$cmgroupsetting = new stdClass();
$cmgroupsetting->configid = $cmsetting->id;
$cmgroupsetting->groupid = $this->group1->id;
$cmgroupsetting->display = 0;
$cmgroupsetting->id = $DB->insert_record('block_ajax_marking_groups', $cmgroupsetting);
$results = $this->get_visibility_array_results($query, $params);
$this->assertEquals(1, count($results));
// Now hide at course level and we ought to get nothing.
$coursesetting = new stdClass();
$coursesetting->userid = $USER->id;
$coursesetting->tablename = 'course';
$coursesetting->instanceid = $this->course->id;
$coursesetting->display = 1;
$coursesetting->id = $DB->insert_record('block_ajax_marking', $coursesetting);
$coursegroupsetting = new stdClass();
$coursegroupsetting->configid = $coursesetting->id;
$coursegroupsetting->groupid = $this->group1->id;
$coursegroupsetting->display = 0;
$coursegroupsetting->id = $DB->insert_record('block_ajax_marking_groups', $coursegroupsetting);
$results = $this->get_visibility_array_results($query, $params);
$this->assertEquals(0, count($results));
// Now override at coursemodule level so we ought to have one only.
$cmgroupsetting->display = 1;
$cmgroupsetting->id = $DB->insert_record('block_ajax_marking_groups', $cmgroupsetting);
$results = $this->get_visibility_array_results($query, $params);
$this->assertEquals(0, count($results));
}
