Allow for searching by parsed prerequisite strings

Fixes a problem with the current search algorithm only finds courses that are contained in prerequisite text, but that doesn't work when the course might be a prefix: ANTH 242/ANTH 242L or when the prerequisite string is written in a format that is not easily read by a machine.

scripts/build_course_db.php

@@ -65,9 +65,17 @@ $edition = new Controller;
$db->exec('ALTER TABLE `crosslistings` ADD INDEX ( `subjectArea` )  ');
$db->exec('ALTER TABLE `crosslistings` ADD INDEX ( `courseNumber` )  ');
+    $db->exec('CREATE TABLE IF NOT EXISTS prereqs (
+    course_id INT UNSIGNED NOT NULL ,
+    subjectArea VARCHAR( 4 ) NOT NULL ,
+    courseNumber VARCHAR( 4 ) NOT NULL
+    );');
+    
+    $db->exec('CREATE INDEX IF NOT EXISTS IX_prereqs_subjectArea_courseNumber ON prereqs ( subjectArea, courseNumber );');
$course_stmt = $db->prepare('INSERT INTO courses (id,subjectArea,courseNumber,title,slo,prerequisite,credits,xml) VALUES (?,?,?,?,?,?,?,?);');
$cross_stmt =  $db->prepare('INSERT INTO crosslistings (course_id, subjectArea, courseNumber) VALUES (?,?,?);');
+    $prereq_stmt = $db->prepare('INSERT INTO prereqs (course_id, subjectArea, courseNumber) VALUES (?,?,?);');
foreach ($courses as $course) {
$id++;
@@ -90,6 +98,14 @@ $edition = new Controller;
}
$values[] = $course->prerequisite;
+        $prereqs = UNL_UndergraduateBulletin_EPUB_Utilities::findCourses($course->prerequisite);
+        foreach ($prereqs as $subj => $courseNums) {
+            foreach ($courseNums as $num) {
+                $prereq_stmt->execute(array($id, $subj, $num));
+            }
+        }
+        unset($subj, $courseNums, $num, $prereqs);
+        
$credits = $course->getCredits();
if (isset($credits['Single Value'])) {