Category rendering, DB columns refined.

repositories/categories.py

@@ -0,0 +1,21 @@
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+from typing import Optional
+
+from db.models import Category
+
+
+class CategoriesRepository:
+    async def get_category_by_id(
+        self, session: AsyncSession, category_id: int
+    ) -> Optional[Category]:
+        stmt = select(Category).where(Category.id == category_id)
+        return await session.scalar(stmt)
+
+    async def get_category_by_parent_id(
+        self, session: AsyncSession, parent_id: Optional[int] = None
+    ) -> list[Category]:
+        stmt = select(Category).where(Category.parent_id == parent_id)
+        result = await session.scalars(stmt)
+
+        return list(result)