diff --git a/backend/capellacollab/alembic/versions/d8cf851562cd_add_missing_empty_model_restrictions.py b/backend/capellacollab/alembic/versions/d8cf851562cd_add_missing_empty_model_restrictions.py
new file mode 100644
index 000000000..c341024c0
--- /dev/null
+++ b/backend/capellacollab/alembic/versions/d8cf851562cd_add_missing_empty_model_restrictions.py
@@ -0,0 +1,43 @@
+# SPDX-FileCopyrightText: Copyright DB Netz AG and the capella-collab-manager contributors
+# SPDX-License-Identifier: Apache-2.0
+
+"""Add missing empty model restrictions
+
+Revision ID: d8cf851562cd
+Revises: 4c58f4db4f54
+Create Date: 2023-08-21 15:45:27.243037
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "d8cf851562cd"
+down_revision = "4c58f4db4f54"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    t_restrictions = sa.Table(
+        "model_restrictions", sa.MetaData(), autoload_with=op.get_bind()
+    )
+
+    restrictions_model_ids = (
+        op.get_bind()
+        .execute(sa.text("SELECT model_id FROM model_restrictions"))
+        .scalars()
+        .all()
+    )
+    models_ids = (
+        op.get_bind().execute(sa.text("SELECT id FROM models")).scalars().all()
+    )
+
+    model_ids_restrictions_null = set(models_ids) - set(restrictions_model_ids)
+
+    for model_id in model_ids_restrictions_null:
+        op.get_bind().execute(
+            t_restrictions.insert().values(
+                model_id=model_id, allow_pure_variants=False
+            )
+        )
diff --git a/backend/capellacollab/projects/toolmodels/crud.py b/backend/capellacollab/projects/toolmodels/crud.py
index 1e39342e9..8032f945a 100644
--- a/backend/capellacollab/projects/toolmodels/crud.py
+++ b/backend/capellacollab/projects/toolmodels/crud.py
@@ -84,6 +84,8 @@ def create_model(
     nature: tools_models.DatabaseNature | None = None,
     configuration: dict[str, str] | None = None,
 ) -> models.DatabaseCapellaModel:
+    restrictions = restrictions_models.DatabaseToolModelRestrictions()
+
     model = models.DatabaseCapellaModel(
         name=post_model.name,
         slug=slugify.slugify(post_model.name),
@@ -92,9 +94,10 @@ def create_model(
         tool=tool,
         version=version,
         nature=nature,
-        restrictions=restrictions_models.DatabaseToolModelRestrictions(),
+        restrictions=restrictions,
         configuration=configuration,
     )
+    db.add(restrictions)
     db.add(model)
     db.commit()
     return model
diff --git a/backend/capellacollab/projects/toolmodels/models.py b/backend/capellacollab/projects/toolmodels/models.py
index 62437248f..0ad5badbe 100644
--- a/backend/capellacollab/projects/toolmodels/models.py
+++ b/backend/capellacollab/projects/toolmodels/models.py
@@ -102,9 +102,7 @@ class DatabaseCapellaModel(database.Base):
         back_populates="model"
     )
 
-    restrictions: orm.Mapped[
-        DatabaseToolModelRestrictions | None
-    ] = orm.relationship(
+    restrictions: orm.Mapped[DatabaseToolModelRestrictions] = orm.relationship(
         back_populates="model", uselist=False, cascade="delete"
     )
 
diff --git a/frontend/src/app/projects/models/model-restrictions/model-restrictions.component.ts b/frontend/src/app/projects/models/model-restrictions/model-restrictions.component.ts
index b84586163..bce5e7c5c 100644
--- a/frontend/src/app/projects/models/model-restrictions/model-restrictions.component.ts
+++ b/frontend/src/app/projects/models/model-restrictions/model-restrictions.component.ts
@@ -11,6 +11,7 @@ import { ToastService } from 'src/app/helpers/toast/toast.service';
 import {
   ModelRestrictions,
   ModelRestrictionsService,
+  areRestrictionsEqual,
 } from 'src/app/projects/models/model-restrictions/service/model-restrictions.service';
 import {
   Model,
@@ -64,31 +65,32 @@ export class ModelRestrictionsComponent implements OnInit {
     });
   }
 
-  private mapRestrictionsFormToToolModelRestrictionsObject(): ModelRestrictions {
-    return {
-      allow_pure_variants:
-        this.restrictionsForm.controls.pureVariants.value || false,
-    };
-  }
-
   private patchRestrictions() {
-    if (
-      JSON.stringify(this.model?.restrictions) ===
-      JSON.stringify(this.mapRestrictionsFormToToolModelRestrictionsObject())
-    ) {
+    if (this.model === undefined || this.projectSlug === undefined) {
+      return;
+    }
+
+    const projectSlug = this.projectSlug;
+    const modelSlug = this.model.slug;
+    const restrictions = this.mapRestrictionsFormToModelRestrictions();
+
+    if (areRestrictionsEqual(this.model.restrictions, restrictions)) {
       return;
     }
 
     this.loading = true;
     this.modelRestrictionService
-      .patchModelRestrictions(
-        this.projectSlug!,
-        this.model!.slug,
-        this.mapRestrictionsFormToToolModelRestrictionsObject()
-      )
+      .patchModelRestrictions(projectSlug, modelSlug, restrictions)
       .subscribe(() => {
-        this.modelService.loadModelbySlug(this.projectSlug!, this.model!.slug!);
+        this.modelService.loadModelbySlug(modelSlug, projectSlug);
         this.loading = false;
       });
   }
+
+  private mapRestrictionsFormToModelRestrictions(): ModelRestrictions {
+    return {
+      allow_pure_variants:
+        this.restrictionsForm.controls.pureVariants.value || false,
+    };
+  }
 }
diff --git a/frontend/src/app/projects/models/model-restrictions/service/model-restrictions.service.ts b/frontend/src/app/projects/models/model-restrictions/service/model-restrictions.service.ts
index 15d32dde7..cbadff5c5 100644
--- a/frontend/src/app/projects/models/model-restrictions/service/model-restrictions.service.ts
+++ b/frontend/src/app/projects/models/model-restrictions/service/model-restrictions.service.ts
@@ -26,6 +26,13 @@ export class ModelRestrictionsService {
   }
 }
 
+export function areRestrictionsEqual(
+  a: ModelRestrictions,
+  b: ModelRestrictions
+): boolean {
+  return a.allow_pure_variants === b.allow_pure_variants;
+}
+
 export type ModelRestrictions = {
   allow_pure_variants: boolean;
 };