Question

我有以下数据库模型和棉花糖架构。该对象将被保存为一个整体。当我们更新对象时，它是通过表单完成的，整个对象会立即更改。发生的问题是，如果我想更改状态并且该ID在数据库中不存在，它只是在创建它并将其添加到表中，而不是抛出一个主键不存在的错误。如何避免这种情况？

class BulkLane(db.Model):
    __tablename__ = "bulk_lane_form"
    id = db.Column(db.Integer, unique=True, primary_key=True)
    statusCd = db.Column("status_cd", db.String(1), db.ForeignKey("status_cd.status_cd"))
    status = db.relationship(Status)
    originId = db.Column("origin_id", db.Integer, db.ForeignKey("supplier_whse.id"))
    origin = db.relationship(SupplierWarehouse)
    workingDaysId = db.Column("working_days_id", db.Integer, db.ForeignKey("work_week.id"))
    workingDays = db.relationship(WorkWeek, foreign_keys=[workingDaysId])
    shippingDaysId = db.Column("shipping_days_id", db.Integer, db.ForeignKey("work_week.id"))
    shippingDays = db.relationship(WorkWeek, foreign_keys=[shippingDaysId])
    transportationDaysId = db.Column("transportation_days_id",
                                 db.Integer, db.ForeignKey("work_week.id"))
    transportationDays = db.relationship(WorkWeek, foreign_keys=[transportationDaysId])



class BulkLaneSchema(marshmallow.ModelSchema):
    class Meta:
        model = BulkLane
        sqla_session = db.session

    id = fields.Integer()
    status = fields.Nested(StatusSchema())
    origin = fields.Nested(SupplierWarehouseSchema())
    workingDays = fields.Nested(WorkWeekSchema())
    shippingDays = fields.Nested(WorkWeekSchema())
    transportationDays = fields.Nested(WorkWeekSchema())


bulk_lane_schema = BulkLaneSchema()
bulk_lanes_schema = BulkLaneSchema(many=True)

如果不存在对象关系，则防止其创建

0 个答案: