Создание и первичная инициализация базы даных успешно завершена. Наполнение демо-данными прошло без ошибок

db/schemas/stock.py

@@ -2,7 +2,7 @@ from datetime import datetime
 from sqlalchemy import Column, DateTime, Float, ForeignKey, Integer, String
 from sqlalchemy.orm import relationship
 
-from db import Base
+from db import Base, CRUD
 import utils
 
 
@@ -14,13 +14,21 @@ class Stock(Base):
         Integer, ForeignKey("toolkits.id", ondelete="CASCADE"), nullable=False
     )
     toolkit_data = relationship(
-        "Toolkit", cascade="all, delete-orphan", lazy="joined", uselist=False
+        "Toolkit",
+        cascade="all, delete-orphan",
+        lazy="joined",
+        uselist=False,
+        single_parent=True,
     )
     toolbox_id = Column(
         Integer, ForeignKey("toolboxes.id", ondelete="CASCADE"), nullable=False
     )
     toolbox_data = relationship(
-        "Toolbox", cascade="all, delete-orphan", lazy="joined", uselist=False
+        "Toolbox",
+        cascade="all, delete-orphan",
+        lazy="joined",
+        uselist=False,
+        single_parent=True,
     )
     quantity = Column(Integer, nullable=False)
     price = Column(Float, nullable=False)
@@ -36,11 +44,7 @@ class Stock(Base):
         return utils.toDict(self)
 
     async def save(self):
-        from db import CRUD
-
         return await CRUD.create(self, refresh=True)
 
     async def edit(self, **kwargs):
-        from db import CRUD
-
         return await CRUD.update(Stock, self.id, **kwargs)