diff --git a/backend/index.js b/backend/index.js
index 9d9316c..945940b 100644
--- a/backend/index.js
+++ b/backend/index.js
@@ -229,7 +229,7 @@ app.post('/api/surveys', async (req, res) => {
   try {
     await query(
       'INSERT INTO survey_results (id, rating, comment, source, reference_id) VALUES (?, ?, ?, ?, ?)',
-      [id, rating, comment, source, referenceId || null]
+      [id, rating, comment || null, source, referenceId || null]
     );
     res.json({ success: true, id });
   } catch (e) {
@@ -244,7 +244,7 @@ app.post('/api/articles', async (req, res) => {
     try {
         await query(
             'INSERT INTO kb_articles (id, title, content, category, type, url, source) VALUES (?, ?, ?, ?, ?, ?, ?)',
-            [id, title, content, category, type, url, source]
+            [id, title, content, category, type, url || null, source || 'manual']
         );
         res.json({ success: true, id, lastUpdated: new Date().toISOString() });
     } catch (e) {
@@ -258,7 +258,7 @@ app.patch('/api/articles/:id', async (req, res) => {
     try {
         await query(
             'UPDATE kb_articles SET title=?, content=?, category=?, type=?, url=? WHERE id=?',
-            [title, content, category, type, url, id]
+            [title, content, category, type, url || null, id]
         );
         res.json({ success: true });
     } catch (e) {