DELETE 语句与 REFERENCE 约束冲突

如何解决DELETE 语句与 REFERENCE 约束冲突

我有一组由以下定义的模型：

from app import db

class SKU(db.Model):
    __tablename__ = 'sku'
    id = db.Column(db.Integer,primary_key=True)
    sku_store_sales = db.relationship('SKUStoreSales',cascade='all,delete')

class Store(db.Model):
    __tablename__ = 'sku'
    id = db.Column(db.Integer,delete')

class SKUStoreSales(db.Model):
    __tablename__ = 'sku_store_sales'
    id = db.Column(db.Integer,primary_key=True)
    sku_id = db.Column(db.Integer,db.ForeignKey('sku.id'))
    store_id = db.Column(db.Integer,db.ForeignKey('store.id'))
    quantity = db.Column(db.Integer,nullable=False)

但是，当我尝试删除 SKU 对象时，出现以下错误：

The DELETE statement conflicted with the REFERENCE constraint "FK__sku_store__sku_i__01D345B0". 
The conflict occurred in database "TEST",table "dbo.sku_store_sales",column 'sku_id'.

请问我哪里出错了？我认为通过在 cascade='all,delete' 和 sku 表中添加 store 可以解决这个问题。