Fixes for table structure

src/backend/InvenTree/common/migrations/0040_parametertemplate_parameter.py

@@ -2,7 +2,6 @@
 
 import InvenTree.models
 import InvenTree.validators
-import common.validators
 from django.conf import settings
 import django.core.validators
 from django.db import migrations, models
@@ -41,9 +40,9 @@ class Migration(migrations.Migration):
                 (
                     "model_type",
                     models.ForeignKey(
-                        blank=True,
+                        blank=True, null=True,
                         help_text="Target model type for this parameter template",
-                        on_delete=django.db.models.deletion.CASCADE,
+                        on_delete=django.db.models.deletion.SET_NULL,
                         to="contenttypes.contenttype",
                         verbose_name="Model type",
                     ),

src/backend/InvenTree/common/migrations/0041_auto_20251028_1112.py

@@ -89,7 +89,7 @@ def copy_part_parameters(apps, schema_editor):
             checkbox=template.checkbox,
             choices=template.choices,
             selectionlist=template.selectionlist,
-            model_type=''
+            model_type=None
         ))
     
     if len(templates) > 0:
@@ -101,13 +101,15 @@ def copy_part_parameters(apps, schema_editor):
     # Next, copy PartParameter instances to Parameter instances
     parameters = []
 
+    content_type = apps.get_model("contenttypes", "ContentType").objects.get(app_label='part', model='part')
+
     for parameter in PartParameter.objects.all():
         # Find the corresponding ParameterTemplate
         template = ParameterTemplate.objects.get(name=parameter.template.name)
 
         parameters.append(Parameter(
             template=template,
-            model_type='part',
+            model_type=content_type,
             model_id=parameter.part.id,
             data=parameter.data,
             data_numeric=parameter.data_numeric,
@@ -121,7 +123,7 @@ def copy_part_parameters(apps, schema_editor):
         Parameter.objects.bulk_create(parameters)
         print(f"\nMigrated {len(parameters)} PartParameter instances.")
 
-    assert Parameter.objects.filter(model_type='part').count() == len(parameters)
+    assert Parameter.objects.filter(model_type=content_type).count() == len(parameters)
 
 
 def copy_manufacturer_part_parameters(apps, schema_editor):
@@ -133,6 +135,8 @@ def copy_manufacturer_part_parameters(apps, schema_editor):
 
     parameters = []
 
+    content_type = apps.get_model("contenttypes", "ContentType").objects.get(app_label='company', model='manufacturerpart')
+
     for parameter in ManufacturerPartParameter.objects.all():
         # Find the corresponding ParameterTemplate
         template = ParameterTemplate.objects.filter(name=parameter.template.name).first()
@@ -143,12 +147,13 @@ def copy_manufacturer_part_parameters(apps, schema_editor):
                 name=parameter.name,
                 description='',
                 units=parameter.units,
+                model_type=None,
                 checkbox=False
             )
 
         parameters.append(Parameter(
             template=template,
-            model_type='manufacturerpart',
+            model_type=content_type,
             model_id=parameter.manufacturer_part.id,
             data=parameter.value,
             data_numeric=convert_to_numeric_value(parameter.value),
@@ -159,7 +164,7 @@ def copy_manufacturer_part_parameters(apps, schema_editor):
         Parameter.objects.bulk_create(parameters)
         print(f"\nMigrated {len(parameters)} ManufacturerPartParameter instances.")
 
-    assert Parameter.objects.filter(model_type='manufacturerpart').count() == len(parameters)
+    assert Parameter.objects.filter(model_type=content_type).count() == len(parameters)
 
 
 class Migration(migrations.Migration):

src/backend/InvenTree/common/models.py

@@ -2476,8 +2476,9 @@ class ParameterTemplate(
     # TODO: Reintroduce validator for model_type
     model_type = models.ForeignKey(
         ContentType,
-        on_delete=models.CASCADE,
+        on_delete=models.SET_NULL,
         blank=True,
+        null=True,
         verbose_name=_('Model type'),
         help_text=_('Target model type for this parameter template'),
     )

src/backend/InvenTree/company/models.py

@@ -298,7 +298,7 @@ class Contact(InvenTree.models.InvenTreeMetadataModel):
 
     @staticmethod
     def get_api_url():
-        """Return the API URL associated with the Contcat model."""
+        """Return the API URL associated with the Contact model."""
         return reverse('api-contact-list')
 
     company = models.ForeignKey(
@@ -383,7 +383,7 @@ class Address(InvenTree.models.InvenTreeModel):
 
     @staticmethod
     def get_api_url():
-        """Return the API URL associated with the Contcat model."""
+        """Return the API URL associated with the Contact model."""
         return reverse('api-address-list')
 
     company = models.ForeignKey(
@@ -586,7 +586,7 @@ class ManufacturerPart(
 
 
 class ManufacturerPartParameter(InvenTree.models.InvenTreeModel):
-    """A ManufacturerPartParameter represents a key:value parameter for a MnaufacturerPart.
+    """A ManufacturerPartParameter represents a key:value parameter for a ManufacturerPart.
 
     This is used to represent parameters / properties for a particular manufacturer part.
 
@@ -891,7 +891,7 @@ class SupplierPart(
     )
 
     def base_quantity(self, quantity=1) -> Decimal:
-        """Calculate the base unit quantiy for a given quantity."""
+        """Calculate the base unit quantity for a given quantity."""
         q = Decimal(quantity) * Decimal(self.pack_quantity_native)
         q = round(q, 10).normalize()