diff --git a/src/covid19/blueprints/common/common_model.py b/src/covid19/blueprints/common/common_model.py
index 7420fa7fea56e3e165482b187f4d6d40f5de04ec..f877c80123835230beb2436eadef7ff572b6a431 100644
--- a/src/covid19/blueprints/common/common_model.py
+++ b/src/covid19/blueprints/common/common_model.py
@@ -72,7 +72,7 @@ class CommonDateReported(db.Model):
     @classmethod
     def remove_all(cls):
         for one in cls.get_all():
-            db.session.delete(one)
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
@@ -140,7 +140,7 @@ class CommonRegion(db.Model):
     @classmethod
     def remove_all(cls):
         for one in cls.get_all():
-            db.session.delete(one)
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/europe/europe_model.py b/src/covid19/blueprints/europe/europe_model.py
index 8d3f91fe01c6c19da75c719e0a7ab4446eb8a8ad..380bf40328067df9cd3422a67d5f71a270538c61 100644
--- a/src/covid19/blueprints/europe/europe_model.py
+++ b/src/covid19/blueprints/europe/europe_model.py
@@ -56,7 +56,7 @@ class EuropeCountry(db.Model):
     @classmethod
     def remove_all(cls):
         for one in cls.get_all():
-            db.session.delete(one)
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/europe/europe_model_import.py b/src/covid19/blueprints/europe/europe_model_import.py
index 74fc93e737e24e9161b7b7703793ae1bb9c9d74f..968fa59beb2bca7a3f71dd6b137fcd38299b8386 100644
--- a/src/covid19/blueprints/europe/europe_model_import.py
+++ b/src/covid19/blueprints/europe/europe_model_import.py
@@ -19,7 +19,7 @@ class EuropeDataImportTable(db.Model):
     @classmethod
     def remove_all(cls):
         for one in cls.get_all():
-            db.session.delete(one)
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/rki/rki_model.py b/src/covid19/blueprints/rki/rki_model.py
index ac30def3eaca75e248aca94152bc62ae87971b5d..1ec387e40613968f216f9fe27841b5421091c709 100644
--- a/src/covid19/blueprints/rki/rki_model.py
+++ b/src/covid19/blueprints/rki/rki_model.py
@@ -49,7 +49,8 @@ class RkiCountry(db.Model):
 
     @classmethod
     def remove_all(cls):
-        db.session.execute("delete from " + cls.__tablename__)
+        for one in cls.get_all():
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/rki/rki_model_import.py b/src/covid19/blueprints/rki/rki_model_import.py
index 00a9055d552e24cfdbec09328b5dbad2f756c331..a145922694d26482c9c810cc927f33ffdbea8e11 100644
--- a/src/covid19/blueprints/rki/rki_model_import.py
+++ b/src/covid19/blueprints/rki/rki_model_import.py
@@ -16,7 +16,8 @@ class RkiGermanyDataImportTable(db.Model):
 
     @classmethod
     def remove_all(cls):
-        db.session.execute("delete from " + cls.__tablename__)
+        for one in cls.get_all():
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/vaccination/vaccination_model_import.py b/src/covid19/blueprints/vaccination/vaccination_model_import.py
index 9dfbbc38f6bc4f3594edc60223aba25eec88335d..ed90437bde504f29162c575e7cf6177f2e4008e3 100644
--- a/src/covid19/blueprints/vaccination/vaccination_model_import.py
+++ b/src/covid19/blueprints/vaccination/vaccination_model_import.py
@@ -29,7 +29,8 @@ class VaccinationGermanyTimeline(db.Model):
 
     @classmethod
     def remove_all(cls):
-        db.session.execute("delete from " + cls.__tablename__)
+        for one in cls.get_all():
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/who/who_model.py b/src/covid19/blueprints/who/who_model.py
index 5887ef594b1f376068476dba33d27534659764d7..e3a2fa8c94789c56ea11a257c853320d19676af7 100644
--- a/src/covid19/blueprints/who/who_model.py
+++ b/src/covid19/blueprints/who/who_model.py
@@ -48,8 +48,8 @@ class WhoCountry(db.Model):
 
     @classmethod
     def remove_all(cls):
-        # TODO: SQLalchemy instead of SQL
-        db.session.execute("delete from " + cls.__tablename__)
+        for one in cls.get_all():
+            db.session.delete(one).cascade()
         db.session.commit()
         return None
 
diff --git a/src/covid19/blueprints/who/who_model_import.py b/src/covid19/blueprints/who/who_model_import.py
index 8b811127cd6f81a14d3ab776272b92981cf848ba..336c5980e149234bae476d4a550df79ea31d7d7b 100644
--- a/src/covid19/blueprints/who/who_model_import.py
+++ b/src/covid19/blueprints/who/who_model_import.py
@@ -16,8 +16,8 @@ class WhoGlobalDataImportTable(db.Model):
 
     @classmethod
     def remove_all(cls):
-        # TODO: SQLalchemy instead of SQL
-        db.session.execute("delete from " + cls.__tablename__)
+        for one in cls.get_all():
+            db.session.delete(one).cascade()
         db.session.commit()
         return None