Implement transaction handling in event deletion: Enhance deleteEvent function to manage foreign key constraints by removing associated EventContactPerson records before deleting the event. This ensures data integrity and improves error handling during the deletion process.

controllers/eventController.js

@@ -1,4 +1,4 @@
-const { Event, Institution, EventPlace, ContactPerson, EventType } = require('../models');
+const { Event, Institution, EventPlace, ContactPerson, EventType, EventContactPerson, sequelize } = require('../models');
 const { Op } = require('sequelize');
 const { startOfDay } = require('date-fns');
 
@@ -163,17 +163,28 @@ const updateEvent = async (req, res) => {
 };
 
 const deleteEvent = async (req, res) => {
+  const transaction = await sequelize.transaction();
   try {
     const { id } = req.params;
+    // Erst Zuordnungen in der Join-Tabelle löschen, damit FK-Constraints erfüllt sind.
+    await EventContactPerson.destroy({
+      where: { event_id: id },
+      transaction,
+    });
+
     const deleted = await Event.destroy({
-      where: { id: id }
+      where: { id: id },
+      transaction,
     });
     if (deleted) {
+      await transaction.commit();
       res.status(204).json();
     } else {
+      await transaction.rollback();
       res.status(404).json({ error: 'Event not found' });
     }
   } catch (error) {
+    await transaction.rollback();
     res.status(500).json({ error: 'Failed to delete event' });
     console.error(error);
   }