set parent_id to null when deleting wiki pages and add migration that fixes invalid entries, fixes #5832

Closes #5832

Merge request studip/studip!4447

1 files changed, 18 insertions, 0 deletions

diff --git a/db/migrations/5.5.35_cleanup_wiki_page_parent_id.php b/db/migrations/5.5.35_cleanup_wiki_page_parent_id.php
new file mode 100644
index 0000000..a374429
--- /dev/null
+++ b/db/migrations/5.5.35_cleanup_wiki_page_parent_id.php
@@ -0,0 +1,18 @@
+<?php
+final class CleanupWikiPageParentId extends Migration
+{
+    public function description()
+    {
+        return 'Remove invalid parent_id from wiki_pages';
+    }
+
+    protected function up()
+    {
+        $query = "UPDATE `wiki_pages` AS w0
+                  LEFT JOIN `wiki_pages` AS w1
+                    ON (w0.`parent_id` = w1.`page_id`)
+                  SET w0.`parent_id` = NULL
+                  WHERE w1.`page_id` IS NULL";
+        DBManager::get()->execute($query);
+    }
+}