diff --git a/RIGS/models.py b/RIGS/models.py
index a3770a51..5617319e 100644
--- a/RIGS/models.py
+++ b/RIGS/models.py
@@ -302,9 +302,9 @@ class Event(models.Model, RevisionMixin):
     )
 
     name = models.CharField(max_length=255)
-    person = models.ForeignKey('Person', null=True, blank=True)
-    organisation = models.ForeignKey('Organisation', blank=True, null=True)
-    venue = models.ForeignKey('Venue', blank=True, null=True)
+    person = models.ForeignKey('Person', null=True, blank=True, on_delete=models.CASCADE)
+    organisation = models.ForeignKey('Organisation', blank=True, null=True, on_delete=models.CASCADE)
+    venue = models.ForeignKey('Venue', blank=True, null=True, on_delete=models.CASCADE)
     description = models.TextField(blank=True, null=True)
     notes = models.TextField(blank=True, null=True)
     status = models.IntegerField(choices=EVENT_STATUS_CHOICES, default=PROVISIONAL)
@@ -323,9 +323,9 @@ class Event(models.Model, RevisionMixin):
     meet_info = models.CharField(max_length=255, blank=True, null=True)
 
     # Crew management
-    checked_in_by = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='event_checked_in', blank=True, null=True)
+    checked_in_by = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='event_checked_in', blank=True, null=True, on_delete=models.CASCADE)
     mic = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='event_mic', blank=True, null=True,
-                            verbose_name="MIC")
+                            verbose_name="MIC", on_delete=models.CASCADE)
 
     # Monies
     payment_method = models.CharField(max_length=255, blank=True, null=True)
@@ -334,7 +334,7 @@ class Event(models.Model, RevisionMixin):
     collector = models.CharField(max_length=255, blank=True, null=True, verbose_name='collected by')
 
     # Authorisation request details
-    auth_request_by = models.ForeignKey('Profile', null=True, blank=True)
+    auth_request_by = models.ForeignKey('Profile', null=True, blank=True, on_delete=models.CASCADE)
     auth_request_at = models.DateTimeField(null=True, blank=True)
     auth_request_to = models.EmailField(null=True, blank=True)
 
@@ -485,7 +485,7 @@ class Event(models.Model, RevisionMixin):
 
 
 class EventItem(models.Model):
-    event = models.ForeignKey('Event', related_name='items', blank=True)
+    event = models.ForeignKey('Event', related_name='items', blank=True, on_delete=models.CASCADE)
     name = models.CharField(max_length=255)
     description = models.TextField(blank=True, null=True)
     quantity = models.IntegerField()
@@ -504,8 +504,8 @@ class EventItem(models.Model):
 
 
 class EventCrew(models.Model):
-    event = models.ForeignKey('Event', related_name='crew')
-    user = models.ForeignKey(settings.AUTH_USER_MODEL)
+    event = models.ForeignKey('Event', related_name='crew', on_delete=models.CASCADE)
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
     rig = models.BooleanField(default=False)
     run = models.BooleanField(default=False)
     derig = models.BooleanField(default=False)
@@ -520,7 +520,7 @@ class EventAuthorisation(models.Model, RevisionMixin):
     uni_id = models.CharField(max_length=10, blank=True, null=True, verbose_name="University ID")
     account_code = models.CharField(max_length=50, blank=True, null=True)
     amount = models.DecimalField(max_digits=10, decimal_places=2, verbose_name="authorisation amount")
-    sent_by = models.ForeignKey('RIGS.Profile')
+    sent_by = models.ForeignKey('RIGS.Profile', on_delete=models.CASCADE)
 
     def get_absolute_url(self):
         return reverse_lazy('event_detail', kwargs={'pk': self.event.pk})
@@ -584,7 +584,7 @@ class Payment(models.Model):
         (ADJUSTMENT, 'TEC Adjustment'),
     )
 
-    invoice = models.ForeignKey('Invoice')
+    invoice = models.ForeignKey('Invoice', on_delete=models.CASCADE)
     date = models.DateField()
     amount = models.DecimalField(max_digits=10, decimal_places=2, help_text='Please use ex. VAT')
     method = models.CharField(max_length=2, choices=METHODS, null=True, blank=True)