Question

我无法从外部表获取属性：

教堂表：

class ChurchModel(db.Model):
    __tablename__ = 'churches'

    church_id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    name = db.Column(db.String(80))

部长表：

class MinisterModel(db.Model):
    __tablename__ = 'ministers'

    minister_id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    name = db.Column(db.String(80))
    home_assembly_id = db.Column(db.Integer)

    church = db.relationship('ChurchModel') # join
    church_id = db.Column(db.Integer, db.ForeignKey('churches.church_id'))

当我尝试这样做时：

church_name = ChurchModel.query.filter_by(church_id=self.church_id).first().name

我收到此错误：

church_name = ChurchModel.query.filter_by(church_id=self.church_id).first().name
AttributeError: 'NoneType' object has no attribute 'name'

Answer 1

尝试一下 church_name = ChurchModel.query.filter(ChurchModel.church_id=self.church_id).first().name

Answer 2

尝试以下

let citiesRef = db.collection("clubs")
.whereField( "owners", arrayContains: 2)
.getDocuments()

根据ID获取名称

2 个答案: