/** Return unsatisfied prerequsites.
*
* Note: code is an sql expression.
*/
static function query_prerequisites($code, $completed, $taking = [], $values = [])
{
global $db;
// Convert all the courses to strings.
foreach ($completed as &$c) {
if (is_a($c, 'Course')) {
$c = $c->getcode();
}
}
foreach ($taking as &$c) {
if (is_a($c, 'Course')) {
$c = $c->getcode();
}
}
// Warning: Dragons Ahead! This is a complex query. With a lot
// of parts.
///// Inner query.
// This inner query counts how many courses in $completed are
// in the elgible group and not in the excluded group.
$haspreq = new Query('coursegroups elg');
$haspreq->select('count(elg.id)');
$haspreq->where('elg.id = prerequisites.eligible');
$haspreq->join('coursegroup_courses elgc', 'elgc.id = elg.id');
// Where the course is in the completed group.
// Or it can be taken concurrently and it is in the taking group.
$haspreq->where('(
elgc.course_code IN ' . Query::valuelistsql($completed) . '
OR (
elgc.course_code IN ' . Query::valuelistsql($taking) . '
AND elgc.concurrent
)
)', array_merge($completed, $taking));
// And it is not one of the courses that is excluded.
$haspreq->where('NOT EXISTS (
SELECT course_code
FROM coursegroup_courses
WHERE coursegroup_courses.id = prerequisites.excluded
AND coursegroup_courses.course_code = elgc.course_code
)', []);
///// Outer Query
// This query selects prerequsites where the number of credits
// earned is less then the required credits.
$q = new Query('prerequisites');
$q->select('course_code');
$q->select('eligible');
$q->select('excluded');
$q->where('course_code = ' . $code, $values);
$q->where('(' . $haspreq->sql() . ') < credits', $haspreq->values());
return $q;
}
public function testInsertStatement_AddValues_Array()
{
$query = new Query("INSERT INTO `test` VALUES (NULL, 'abc', 10)");
$query->values(array(null, 'xyz', 12));
$this->assertEquals("INSERT INTO `test` VALUES (NULL, 'abc', 10), (DEFAULT, \"xyz\", 12)", (string) $query);
}
