Split DB Updates into seperate files, with the cutoff being 2.0.0

admin/database_updates/2.0.4.php

@@ -0,0 +1,20 @@
+<?php
+
+/*
+ * ITFlow - Database update to version 2.0.4 (from 2.0.3)
+ * Included by admin/database_updates.php - do not access directly
+ */
+
+defined('FROM_DB_UPDATER') || die("Direct file access is not allowed");
+
+    // Clean up orphaned history
+    mysqli_query($mysqli, "
+        DELETE FROM `certificate_history`
+        WHERE `certificate_history_certificate_id` NOT IN (SELECT `certificate_id` FROM `certificates`);
+    ");
+
+    // Add foreign key certificate history
+    mysqli_query($mysqli, "
+        ALTER TABLE `certificate_history`
+        ADD FOREIGN KEY (`certificate_history_certificate_id`) REFERENCES `certificates`(`certificate_id`) ON DELETE CASCADE
+    ");