utility to find empty fields on databse classes: for tidying

core/management/commands/find_empty_fields.py

@@ -0,0 +1,124 @@
+from django.core.management.base import BaseCommand
+from django.apps import apps
+from django.db.models import Q, CharField, TextField
+
+"""Completely written by https://gemini.google.com/ 2.5
+"""
+
+def get_all_project_models():
+    """
+    Returns a list of all concrete model.Model classes in the Django project.
+    It ignores abstract models and models from third-party apps that aren't
+    part of the project's own apps.
+    """
+    # You can customize this list to include/exclude specific apps
+    # For example: installed_apps = settings.INSTALLED_APPS
+    all_models = []
+    # This gathers all models from all installed apps.
+    for app_config in apps.get_app_configs():
+        all_models.extend(list(app_config.get_models()))
+    return all_models
+
+
+def find_empty_or_null_fields(model_class):
+    """
+    Takes a model class and checks every field.
+
+    Returns a list of field names for which all database entries
+    are either NULL or an empty string.
+    """
+    completely_empty_fields = []
+    
+    # Get the total number of records for this model.
+    total_records = model_class.objects.count()
+
+    # If there are no records, all fields are technically "empty".
+    # We return an empty list to avoid reporting every field from an empty table.
+    if total_records == 0:
+        return []
+
+    # Iterate over all concrete fields of the model.
+    for field in model_class._meta.get_fields():
+        # We only want to check actual database columns, not relations.
+        if not hasattr(field, 'column'):
+            continue
+
+        field_name = field.name
+        
+        # Build a query to find records that have a meaningful value.
+        # This is more efficient than counting all null/empty records.
+        # We exclude records that are NULL.
+        query_has_value = model_class.objects.exclude(Q(**{f'{field_name}__isnull': True}))
+        
+        # For text-based fields, we also exclude empty strings.
+        if isinstance(field, (CharField, TextField)):
+            query_has_value = query_has_value.exclude(Q(**{f'{field_name}': ''}))
+
+        # If the query for records WITH a value returns FALSE (no such records exist),
+        # it means all records for this field are empty or null.
+        if not query_has_value.exists():
+            completely_empty_fields.append(field_name)
+
+    return completely_empty_fields
+
+
+class Command(BaseCommand):
+    help = "Scans all project models to find fields where all entries are empty or null."
+
+    def handle(self, *args, **options):
+        self.stdout.write(self.style.SUCCESS("🚀 Starting scan for empty or null fields across all models..."))
+        
+        all_models = get_all_project_models()
+        found_any = False
+
+        for model in all_models:
+            total_records = model.objects.count()
+            model_name = f"{model._meta.app_label}.{model._meta.object_name}"
+            self.stdout.write(f"\n🔍 Checking model: {self.style.HTTP_INFO(model_name)} ({total_records} instances found)")
+
+            empty_fields = find_empty_or_null_fields(model)
+
+            if empty_fields:
+                found_any = True
+                for field_name in empty_fields:
+                    self.stdout.write(
+                        self.style.WARNING(f"  -> Field '{field_name}' is completely empty or null.")
+                    )
+            else:
+                self.stdout.write(self.style.SUCCESS("  ✅ All fields contain data."))
+
+        if not found_any:
+            self.stdout.write(self.style.SUCCESS("\n🎉 Scan complete. No fields were found to be universally empty or null."))
+
+
+"""
+
+### How to Run the Command
+
+After saving the file, you can run your new command from your project's root directory (where `manage.py` is located):
+
+bash
+uv run manage.py find_empty_fields
+
+
+### Example Output
+
+The output in your terminal will look something like this:
+
+```
+🚀 Starting scan for empty or null fields across all models...
+
+🔍 Checking model: auth.Group
+  ✅ All fields contain data.
+
+🔍 Checking model: auth.User
+  -> Field 'last_name' is completely empty or null.
+  -> Field 'first_name' is completely empty or null.
+
+🔍 Checking model: products.Product
+  -> Field 'notes' is completely empty or null.
+  -> Field 'discount_code' is completely empty or null.
+
+🔍 Checking model: products.Category
+  ✅ All fields contain data.
+"""