yet another refactor

src/models/category.py

@@ -1,7 +1,9 @@
 from pydantic import Field, computed_field
 from sqlalchemy import ForeignKey, String, UniqueConstraint
-from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy.orm import Mapped, Session, mapped_column, relationship
 
+from src.db_utils import upsert
+from src.models.category_budget import CategoryBudgetDb
 from src.models.common import BaseModelDb, ExportBaseModel, hashify
 
 
@@ -53,4 +55,22 @@ class CategoryDb(BaseModelDb):
         "CategoryDb", remote_side="CategoryDb.id", back_populates="children"
     )
     children = relationship("CategoryDb", back_populates="parent")
-    budgets = relationship("CategoryBudgetDb", back_populates="category")
+    budgets: Mapped[list[CategoryBudgetDb]] = relationship(back_populates="category")
+
+
+def upsert_category(
+    session: Session, category: Category | None, do_commit: bool = True
+) -> CategoryDb | None:
+    if category is None:
+        return None
+
+    parent = upsert_category(session, category.parent, do_commit=False)
+    parameters = {"name": category.name, "parent": parent}
+    return upsert(
+        session,
+        CategoryDb,
+        parameters,
+        parameters,
+        do_update=False,
+        do_commit=do_commit,
+    )