Flask SQLAlchemy 查询 model 不返回外键

Question

我有以下课程：

class CompanyModel(db.Model):
    __tablename__ = "tb_company"
    __table_args__ = {"schema": "public"}

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100))


class CustomerModel(db.Model):
    __tablename__ = "tb_customer"
    __table_args__ = {"schema": "public"}

    id = db.Column(db.Integer, primary_key=True)
    company_id = db.Column(db.Integer,
                           db.ForeignKey(CompanyModel.id),
                           nullable=False)

    company = db.relationship("CompanyModel",
                              foreign_keys=company_id,
                              backref=db.backref("company",
                                                 uselist=False))

但是，当我查询它时，外键不会显示：

{
    "id": 79
}

我什至尝试在查询中手动设置其属性，但无论如何都行不通：

@classmethod
def find_by_id(cls, customer_id: int) -> "CustomerModel":
    customer = cls.query.filter_by(id=customer_id).first()
    setattr(customer, "company_id", customer.company.id)
    return customer

Answer 1

我已经设法解决了。 刚刚将该字段添加到 Flask-Marshmallow 的自动架构中：

class CustomerSchema(ma.SQLAlchemyAutoSchema):
    class Meta:
        model = CustomerModel
        load_instance = True

    id = ma.auto_field(dump_only=True)
    company_id = ma.auto_field(dump_only=True)

但是，我仍然有一个问题......我想使用“CompanyModel”中的另一个字段作为查询结果，例如“名称”列。 但是，当我尝试手动设置它时，出现以下错误：

ValueError: invalid literal for int() with base 10: 'Company Name'

我该怎么做？