diff --git a/pfbudget/db/model.py b/pfbudget/db/model.py
index 0c12deb..83fe446 100644
--- a/pfbudget/db/model.py
+++ b/pfbudget/db/model.py
@@ -252,10 +252,6 @@ class CategoryGroup(Base, Serializable):
 
     name: Mapped[str] = mapped_column(primary_key=True)
 
-    categories: Mapped[list[Category]] = relationship(
-        default_factory=list, lazy="joined"
-    )
-
     def serialize(self) -> Mapping[str, Any]:
         return super().serialize() | dict(name=self.name)
 
@@ -524,6 +520,7 @@ class CategoryRule(Rule):
 
     __mapper_args__ = {
         "polymorphic_identity": "category_rule",
+        "polymorphic_load": "selectin",
     }
 
 
@@ -542,4 +539,5 @@ class TagRule(Rule):
 
     __mapper_args__ = {
         "polymorphic_identity": "tag_rule",
+        "polymorphic_load": "selectin",
     }
diff --git a/tests/test_backup.py b/tests/test_backup.py
index fe824b0..87bae30 100644
--- a/tests/test_backup.py
+++ b/tests/test_backup.py
@@ -17,6 +17,7 @@ from pfbudget.db.client import Client
 from pfbudget.db.model import (
     Bank,
     BankTransaction,
+    Base,
     Category,
     CategoryGroup,
     MoneyTransaction,
@@ -123,9 +124,6 @@ class TestBackup:
 
         client = MockClient()
         client.insert([e for t in params for e in t[0]])
-        originals = client.select(Transaction)
-
-        assert originals
 
         command = BackupCommand(client, file, ExportFormat.JSON)
         command.execute()
@@ -134,6 +132,13 @@ class TestBackup:
         command = ImportBackupCommand(other, file, ExportFormat.JSON)
         command.execute()
 
-        imported = other.select(Transaction)
+        def subclasses(cls: Type[Any]) -> set[Type[Any]]:
+            return set(cls.__subclasses__()) | {
+                s for c in cls.__subclasses__() for s in subclasses(c)
+            }
 
-        assert originals == imported
+        for t in [cls for cls in subclasses(Base)]:
+            originals = client.select(t)
+            imported = other.select(t)
+
+            assert originals == imported, f"{t}"